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PROLEGOMENA LOGICA: 



AN INQUIRY 



THE PSYCHOLOGICAL CHARACTER OF 
LOGICAL PRO€ESSES. 

HENRY LONGUEVILLE MANSEL, B.D., LL.D. 

WAYNFLETE PROFESSOR OF MORAL AND METAPHYSICAL PHILOSOPHY, OXFORD ; 

EDITOR OF SIR WILLIAM HAMILTON'S LECTURES; AUTHOR OF 

"LIMITS OF RELIGIOUS THOUGHT," ETC. ETC. 



La Logique n'est qu'un retour de la Psychologie sur elle-meme. 

Cousin - . 



FIRST AMERICAN, FROM THE SECOND ENGLISH EDITION, 
CORRECTED AND ENLARGED. 



BOSTON: 

GOULD AND LINCOLN, 

59 WASHINGTON STREET. 

NEW YORK: SHELDON AND COMPANY. 
CINCINNATI: GEORGE S. BLANCHARD. 

1860. 



2 



OS 



fir 



THE LIBRARY 
Of C OHOM M 

[WAtHmOTOH 

Entered according to Act of Congress, in the year 1860, by 
GOULD AND LINCOLN, 

In the Clerk's Office of the District Court for the District of Massachusetts. 



And over : 
Elcctrotijped and Printed by W. F. Draper. 



PREFACE-. 



A portion of the following pages has already appeared in 
two Articles contributed by the Author to the North British 
Review} The present Work is an attempt to exhibit more 
fully the relations there intimated as existing between Logic 
and Psychology, with some additional matters, which could not 
be included within the limits of a Review. The title of the 
work is not meant to imply that it contains an introduction to 
Logic, or is designed for the use of those unacquainted with 
its rudiments. On the contrary, without some previous knowl- 
edge of the elementary portion of that science, the greater 
part of the present volume will not be intelligible. But it 
is intended as an inquiry into that which in the order of 
nature is prior to Logic ; though in the order of time it is 
of later scientific development, and in the order of study 
should be postponed till after an acquaintance at least with 
the elements of logical science ; — an inquiry into a subject 
which is indicated by every page of Logic in which mind and 

1 No. 27 : Art. Philosophy of Language. No. 29 : Art. Becent Extensions 
of Formal Logic. 



IV PREFACE. 

its operations are mentioned, and which is the touchstone by 
which the whole truth and scientific value of Logic must ulti- 
mately be tested ; — an inquiry into the constitution and laws 
of the thinking faculty, such as they are assumed by the 
Logician as the basis of his deductions. It may, therefore, 
be regarded as an attempt to prosecute, in relation to Logic, 
the inquiry instituted by the Prolegomena of Kant in relation 
to Metaphysics ; namely, What are the psychological condi- 
tions under which a scientific system is possible ; and what, in 
conformity to those conditions, are the characteristic features 
which such a system must exhibit ? It is not intended as 
a complete treatise, either on Psychology alone, or on Logic 
alone ; but as an exposition of Psychology in relation to 
Logic, containing such portions of the former as are abso- 
lutely necessary to the vindication and even to the under- 
standing of the latter. 

That something of the kind is not altogether unneeded, will 
be acknowledged by those who are acquainted with the litera- 
ture of the subject. During the last and present century, 
under the influence of the Critical Philosophy of Kant, For- 
mal Logic, in itself and in its relations to Psychology, has 
been elaborated by numbers of eminent writers in Germany, 
from whose labors the English student has, as yet, derived 
hardly any benefit. Misconceptions are still allowed to prevail 
concerning the nature and office of Logic, which the slightest 
acquaintance with the actual constitution of human thought 
and its laws would suffice to dissipate forever. Matters 



PREFACE. V 

treated of by different logicians are alternately expelled from 
and restored to the province of the science, without the ap- 
pearance of anything like a sound canon of criticism to deter- 
mine what is logical and what is not. Attack and defence of 
the study have been conducted on grounds equally untenable ; 
and a conception of Logic as it might be were the human 
mind constituted as it is not, is frequently tossed to and fro 
between contending parties, to the exclusion of Logic as it 
must be while the human mind is constituted as it is. 

But if an exposition of Psychology in relation to Logic is 
thus needed for a distinct conception of the latter science in 
itself, it is not less needed when we look to the conditions 
under which that science may be most profitably employed as 
a branch of academical study. Few who are acquainted with 
the various logical systems of modern times will hesitate to 
give a decided preference over all others to the formal view 
of the science, which from the days of Kant has gradually 
been advancing to perfection. Whether we regard the unity 
and scientific completeness of the system itself, the great 
names by which it is supported, the valuable works that 
might easily be made available for its communication, or 
the facility with which it might be introduced into the exist- 
ing course of study, in all it possesses unquestionable advan- 
tages, as the basis of logical instruction. But, on the other 
hand, its compass is small ; and its contents, though clear and 
definite, are, taken by themselves, too meagre to be an ade- 
quate substitute for the miscellaneous reading which is so 

1# 



VI PREFACE. 

often misnamed Logical. To supply this defect, two courses 
are open. The study of Formal Logic may be combined 
either with its objective or with its subjective applications. 
We may treat, that is to say, a system of Logic, either in 
connection with some of the various objects of thought to 
which it may in practice be applied, or in relation to the 
thinking mind, and to that mental philosophy of which it forms 
a portion. The former method has been abundantly tried, 
and has abundantly failed in the trial. A system of Logic 
treated in its objective application has no alternative between 
an impossible universality or an arbitrary exclusiveness. By 
whatever right one iota of the matter of thought can claim 
admission into the system, by the same right the whole uni- 
verse of human knowledge is entitled to follow. Such a 
method can only be employed as a bad means of collecting 
desultory information on unconnected subjects. As a system, 
it postulates its own failure. 

It is in connection, not in confusion, with cognate sciences, 
as a branch of mental philosophy, that Logic may and ought 
to be studied. One of the objects of the present work is to 
show that Logic as a science cannot be rightly understood and 
appreciated, except in relation to Psychology. The neglect 
of this relation has been acknowledged as the weak side of 
the Kantian Philosophy; 1 its recognition has been impera- 
tively demanded by the ablest modern writers on the subject. 

1 See Fries, System der Logik, p. 22. 



PREFACE. VII 

"Selon moi," says M. Duval-Jouve, "Tobjet de la logique 
n'est pas seulement la direction de 1'intelligence, mais encore 
V etude de l'intelligence ; la direction apres l'etude ; et un traite 
de logique doit comprendre la description du fait intellectuel, 
la theorie de ses lois, l'expose des regies qu'il doit reconnaitre, 
soit dans son etat psychologique et de pure pensee, soit dans sa 
manifestation par la parole." 1 The propriety of including 
these psychological matters in a Treatise on Logic may be 
questioned ; but to the necessity of including them in a phi- 
losophical course, of which Logic should form a portion, the 
whole history of the science bears witness. The alliance 
established of old between Logic and Metaphysics was dis- 
solved by the Critical Philosophy of Kant, and cannot be 
restored, except by identifying the two, with Hegel. To those 
who reject this alternative a blank is made in philosophical 
study, which can only be adequately supplied by a well-con- 
nected course of Mental Science, embracing, as its constituent 
portions, the three cognate subjects of Logic, Ethics, and 
Psychology. 

To Ethics, as well as to Logic, Psychology is an indispensa- 
ble supplement. The science of man as he ought to be must 
be based on that of man as he is. In Moral Philosophy, as in 
Logic, questions of a psychological character meet us at every 
stage of our course ; and the value of every ethical system 
must ultimately be tested on psychological grounds. Perhaps 

1 Traite de Logique, Preface, p. viii. 



VIII PREFACE. 

it is not too much to say, that half the ethical systems which 
have been at different times in vogue, have started from a 
psychological assumption, which, consistently carried out, would 
make Ethical Philosophy impossible. 

May I be allowed to suggest a still higher application of 
the same criterion ? In the very conception of Revealed 
Religion, as a communication from an Infinite to a finite 
Intelligence, is implied the existence of certain ideas of a 
purely negative character, the purpose of which is not spec- 
ulative but regulative truth ; which are designed, not to sat- 
isfy our reason, but to guide our practice. These, from their 
very nature, are beyond the criticism of reason. Rut in order 
to discriminate accurately between the provinces of reason 
and faith, to determine what we may and what we may not 
seek to comprehend as a speculative truth, an examination of 
the limits of man's mental powers is indispensable. The 
ground of many a controversy might be considerably nar- 
rowed were we to inquire at the outset what are the mental 
powers that can be brought to the solution of the question, and 
how are they related to the data on which they must operate. 
Fichte made his earliest attempt, as a disciple of the Kantian 
philosophy, by an Essay towards a Critique of every Revela- 
tion. The positive portion of his principles of criticism (for 
many of them have a negative character only) might be better 
applied to a Critique of every Critique of Revelation ; — an 
inquiry, that is to say, what portion of the contents of Revela- 



PREFACE. IX 

tion, as addressed to human minds, can be wrought by human 
interpretation into the form of speculative dogmas. 

" La psychologie," says M. Cousin, " n'est assurement pas 
toute la philosophie, mais elle en est le fondement." If there 
be any truth in this saying of one of the highest philosophical 
authorities of our own or of any age, it will follow of neces- 
sity that a course of instruction in this fundamental branch 
must be an integral and indispensable portion of any system 
of philosophical teaching. 

The psychological criticisms of the present work are mainly 
limited to logical questions, and are designed to throw some 
light on matters which, almost from the commencement of my 
logical studies, have appeared to me to stand in especial need 
of elucidation. Much of what has been acquired from foreign 
sources, with much labor and little guidance in the search, 
might have been learned in an easier and more direct manner, 
had the course which I have ventured to recommend been 
adopted in relation to my own early studies. The numerous 
obligations which the work is under to previous writers are 
most of them acknowledged as they occur. One or two, how- 
ever, demand an express mention here. The reader who is 
familiar with Kant's writings will probably discern obligations 
to the Critical Philosophy in almost every page ; even where 
the language of Kant has been departed from, and the differ- 
ence in detail is such as would not justify a direct reference to 
his works. The method and material for thinking derived 



X PREFACE. 

from the study of the Kantian philosophy is in many respects 
far more valuable than the direct information communicated. 
This is especially the case with a student who views that 
philosophy from the psychological rather than the metaphys- 
ical side, in its relation to Hume and Locke rather than to 
Wolf and Leibnitz, and who endeavors to combine the mate- 
rials thence obtained with the most valuable results of the 
Scottish philosophy, which owes its rise, like the Kantian, to 
the skepticism of Hume. 

To two other eminent philosophers a similar acknowledg- 
ment is due. The G-erman side of M. Cousin's Eclecticism 
approaches, in aim at least, if not in method, nearer to the 
philosophy of Schelling and Hegel than to that of Kant. It 
is natural, therefore, that his view of the limits of human 
thought, and consequently of the province of Logic and of its 
relation to Psychology, should contain much which cannot be 
directly transferred to the pages of a work which advocates a 
strictly formal view of Logic, and which would rather contract 
than enlarge the limits assigned by Kant to the Understanding 
and the Reason. But the writings of M. Cousin are indis- 
pensable to all who would gain a true estimate of the impor- 
tance of Psychology and its position in a philosophical course ; 
and the benefits which I am conscious of having derived from 
their study are far more than can be adequately expressed 
by a direct acknowledgment of passages borrowed from them. 
From the author's view of the office of Logic I have departed 
widely ; which makes it the more necessary to confess the 



PREFACE. XI 

numberless advantages derived from his writings, in relation 
to almost every point treated of in the following pages. 

In many points in which I have departed from the doc- 
trines of the great Eclectic, I am much indebted to the 
writings of his illustrious critic, Sir William Hamilton. The 
same acknowledgment may indeed be made in relation to 
nearly the whole contents of the present volume, partly by 
way of direct obligation, and still more by way of hints and 
suggestions of questions to be solved, and the method of their 
solution. I cannot, indeed, claim the sanction of this eminent 
authority for any statement which is here advanced, except 
where direct reference is made to his writings ; yet probably 
even where I have differed from him in opinion, there is 
much that would never have been written at all but for 
the valuable aid furnished by him. To say that I have 
occasionally ventured to dissent from the positions of each 
and all of the philosophers to whom I am so much indebted, 
is only to say that I have endeavored to study their works 
in the spirit in which they would wish to be studied — with the 
respect and gratitude of a disciple, but, it is hoped, without 
the servility of a copyist. 

For the phraseology which I have occasionally been com- 
pelled to employ in the course of the following remarks, 
no apology will be required by those acquainted with the 
history of mental science. In no branch of study is it so 
necessary to observe the Aristotelian precept, ovo^aroTromlv 



XII PREFACE. 

aacpr)V€ias eVe/cei/. Nine-tenths of the confusion and contro- 
versy that have existed in this department are owing to 
that unwillingness to innovate in matters of language, which 
leads to the employment of the same term in various shades 
of meaning, and with reference to various phenomena of 
consciousness. In this respect philosophy is under deep 
obligations to the purism of German writers, which has en- 
abled subsequent thinkers to examine the most important 
problems of Psychology apart from the old associations of 
language. A new phraseology may occasion some little dif- 
ficulty at the outset of a work ; but to adhere to an inade- 
quate vocabulary merely because its expressions are estab- 
lished, is to involve the whole of the subject in hopeless 
confusion and obscurity. In this respect, however, I trust 
I shall not be found to have departed from authorized lan- 
guage in a greater degree than is absolutely necessary for 
the purpose of communicating to English readers some of 
the most valuable results of German thought, and of carrying 
into effect the main design of the present Essay, — that of 
testing the received processes of Logic, by reference to the 
facts of human consciousness. 



CONTENTS 



CHAPTER I. 



PAGE 

ON THOUGHT, AS DISTINGUISHED FROM OTHER FACTS OF 

CONSCIOUSNESS, . 15 



CHAPTER II. 

ON THE THREE OPERATIONS OF THOUGHT, ... 59 



CHAPTER III. 



ON LAW, AS RELATED TO THOUGHT AND OTHER OBJECTS, 7G 



CHAPTER IV. 

ON THE PSYCHOLOGICAL CHARACTER OF MATHEMATICAL 

NECESSITY, ' . 92 

2 



XIV CONTENTS 



CHAPTER V. 

PAGE 

ON THE PSYCHOLOGICAL CHARACTER OF METAPHYSICAL 

NECESSITY, 113 



CHAPTER VI. 

ON LOGICAL NECESSITY AND THE LAWS OF THOUGHT, . 155 

CHAPTER VII. 

ON THE MATTER AND FORM OF THOUGHT, ... 204 

CHAPTER VIII. 

ON POSITIVE AND NEGATIVE THOUGHT, ... 221 

CHAPTER IX. 

ON LOGIC AS RELATED TO OTHER MENTAL SCIENCES, . 232 

APPENDIX, 257 



PEOLEGOMBNA LOGICA. 



CHAPTER I, 



ON THOUGHT, AS DISTINGUISHED FROM OTHER FACTS OF 

CONSCIOUSNESS. 

Without entering into the countless disputes which 
have taken place concerning the nature and definition 
of Logic, 1 it is sufficient to observe that it will be treated 
in the following pages, in accordance principally with the 
views of Kant, as the Science of the Laws of Formal 
Thinking. In the wide sense, indeed, in which the term 
is used by Archbishop Whately, it may be admitted that 
Logic, as furnishing rules to secure the mind from error in 
its deductions, is also an Art, or, to speak more correctly, 
a Practical Science. 2 Still, it may be questioned whether 
the practical service thus performed by Logic can with 
propriety be allowed to influence its definition. The 

1 For a summary of various opinions on this question, see Zabarella, de 
Natura Logicce, lib. i. ; Smiglecii Logica, Disp. ii. Qu. v. ; Burgersdicii Inst. 
Log. lib. i. cap. 1, and Sir W. Hamilton, Edinburgh Review, No. 115, p. 203. 

2 For the distinction between these terms, see Wolf, Phil. Bat. Proleg., 
§ 10. " Omnis Logica utens est habitus, qui proprio exercitio comparatur, 
minime autem discendo acquiritur, adeoque et ipsa doceri nequit. Quam- 
obrem, cum Logica omnis vel sit docens vel utens, neque enim preeter 
regularum notitiam atque habitum eas ad praxin transferendi tertium 



16 PROLEGOMENA LOGICA. 

benefits performed by Logic as a medicine of the mind, 
however highly we may be disposed to rate them, are 
accidental only, and arise from causes external to the 
Science itself: its speculative character, as an inquiry into 
the laws of thought, is internal and essential. To the 
twofold character of Logic two conditions are necessary. 
Firstly, that there exist certain mental laws to which 
every sound thinker is bound to conform. Secondly, that 
it is possible to transgress those laws, or to think unsoundly. 
On the former of these conditions depends the possibility 
of Logic as a speculative Science ; on the latter, its possi- 
bility as a practical Science or Art. Now, if we look at 
these two conditions with reference to the actual contents 
of pure Logic, it is manifest that the abrogation of the first 
would utterly annihilate the whole Science; whereas the 
abrogation of the second would at most only necessitate 
the removal of a few excrescences, leaving the main body 
of Logical doctrine substantially as it is at present. Sup- 
pose, for example, that the difference between sound and 
unsound reasoning could be discerned in individual cases 
as a matter of fact, but that we had no power of classifying 
the several instances of each and referring them to certain 
common principles. It is clear that, under such a supposi- 
tion, the present contents of Logic, speculative and prac- 
tical, could have no existence. The number of sound and 
unsound thinkers in the world might remain much as it is 
now, but the impossibility of investigating the principles 
of the one and applying them to the correction of the 
other would make an Art or Science of Logic unattainable. 

concipi potest; sola Logica artificialis docens ea est, quse doceri adeoque 
in numerum disciplinarum philosophicavum referri potest. Atque ideo 
quoque Logicam definivimus per scientiam, minime autem per artem vel 
habitum in gcnere, quod genus convenit Logica? utenti." 



PROLEGOMENA LOGICA. 17 

But let us imagine, on the other hand, a race of intelligent 
beings, subject to the same laws of thought as mankind, 
but incapable of transgressing them in practice. The 
elements of existing Logic, the Concept, the Judgment, 
the Syllogism, would remain unaltered. The Science 
of Logic would investigate the laws of unerring Reason, 
as the Science of Astronomy investigates the unvarying 
laws of the heavenly phenomena ; but an Art of Logic, to 
preserve the mind from error, would be as absurd as an 
Art of Astronomy proposing to control and regulate the 
planets in their courses. From these considerations it 
follows that, even granting Logic to be, under existing 
circumstances, both Science and Art, yet the former is 
an essential, the latter an accidental, feature ; the one is 
necessarily interwoven with the elements of the system, 
the other a contingent result of the infirmities of those 
who possess it. In this respect, pure Logic may not 
unfairly be compared to Mechanics treated as a branch 
of Mathematics. As Sciences, both proceed deductively 
from assumptions more or less inconsistent with the actual 
state of things. As Arts, neither can be put in practice 
without making allowance for contingencies neglected in 
the scientific theory. The assumed logical perfection of 
thought bears about the same relation to the ordinary 
state of the human mind as the assumption of perfectly 
rigid levers and perfectly flexible cords bears to the action 
of those instruments in practice. But, on the other hand,, 
the possibility of making such allowances implies that the 
difference between practice and theory is one of degree 
only, and not of kind. The instrument as used may not 
be identical with the instrument as contemplated, but it 
must be supposed capable of approximation to it. A Sci- 
ence of the Laws of Thought is only valuable in so far as 

. 9* 



18 PROLEGOMENA LOGTCA. 

its laws are acknowledged to be those to which actual 
thinking ought, as far as possible, to conform, and which, 
if fully complied with, would represent only the better 
performance of existing obligations, not the imposition of 
new ones. The same may be said of Ethical Philosophy 
likewise. In describing the perfection of moral and intel- 
lectual virtue, we describe a standard to which, in the 
existing state of human nature, no man does or can 
attain ; but the whole value of the portrait is derived 
from its being a more or less accurate representation of 
man as he ought to be, not the imaginary sketch of a being 
of a totally distinct kind. 1 

In order therefore to the right appreciation of any given 
system of Logic, it becomes necessary to ask, What is the 
actual nature of Thought as an operation, to what laws is 
it subject, and to what extent are they efficient? This 
inquiry does not, strictly speaking, fall within the province 
of Logic itself. No Science is competent to criticise its 
own principles. That there is such an operation as think- 
ing, and certain laws to which it is bound to conform, the 
Logician does not question, but assumes. Whether there 
are other mental operations besides thinking, and whether 
these must act in combination with Thought for the at- 
tainment of any special class of truths ; — these and such 
like questions it is beyond his province to investigate. His 
own branch of inquiry is twofold, partly constructive, and 
partly critical. In the former capacity, he inquires, what 
are the several forms, legitimate or illegitimate, which 

1 "Beide, Logik und Ethik, haben Vorschriften aufzustellen, nach welchen 
sich, titer das Denken, dort das Handeln richten soil, obgleick es sicli eins 
wie das andere, aus psychologischen Griinden gar oft in der Wirklichkeit 
nicht damach richtet, und niclit darnach richten kann."— Herbart. Psy- 
chol ogie als Wissenschaft, Th. ii. § 119. 



PROLEGOMENA LOGICA. 19 

Thought as a product will assume, according as the act of 
thinking is or is not conducted in conformity to its given 
laws. In the latter capacity, he sifts and examines the 
special products of this or that thinker, and pronounces 
them, according to the features which they exhibit, to be 
legitimately produced or otherwise. 1 

Beyond the boundaries of pure Logic there is thus 
another and important field of inquiry. Is the mind capa- 
ble of other operations besides those of Thought ; and are 
there other kinds of mental rectitude besides that which 
results from the conformity of Thought to its own laws ? 
Do the several mental faculties act in the pursuit of truth 
coujointly or separately ? Does each process guarantee 
the complete attainment of a limited class of truths, or 
the attainment of a single element which becomes truth 
only in combination? Do the Laws of Thought, as as- 
sumed by Logic, exhibit those features which, from the 
general constitution of the human mind and the peculiar 
character of the thinking faculty, they might be expected 
to exhibit? In relation to these and similar questions, 
Logic is subordinate to Psychology. 

To Psychology we must look for the explanation and 
justification of the peculiar features of Logic. Logic, says 
one antagonist, furnishes no criterion of material truth 
and falsehood. It may be that, from the constitution of 
the human mind, such a criterion is impossible. Its prin- 
ciples, says another, are mere frivolous tautologies. It 
may be that this very tautology has a psychological sig- 
nificance, that it is the necessary consequence of a mind 
gazing upon its own laws. It is barren in the production 



1 See Clauberg, Logica, Proleg. § viii. Drobisch, New Darstellung der 
Logik, § 9. Fries, System der Logik, § 1. 



20 PROLEGOMENA LOGIC A. 

of positive science. It may be that Thought alone was 
never designed by man's Maker to be otherwise. As an 
instrument, it has attempted much and accomplished little. 
The fault may lie, not in the tool, but in the workman. 
Before we condemn Logic for what it does not perform, or 
despise it for what it does, it may be as well to ask, what 
we may learn elsewhere of the nature of the thinking 
faculty, and what it may reasonably be expected to ac- 
complish. 

In order, therefore, to determine accurately the province 
and capabilities of Logic, it will be necessary to examine 
the psychological distinction between Thought, properly 
so called, and other phenomena of mind. This being as- 
certained, there will remain the inquiry, in what manner 
our consciousness itself and the several objects submitted 
to it may be regarded as subject to law ; what are the dif- 
ferent classes of laws, whether of the subject or of the 
object, the characteristic features of each, their mode of 
determining the several operations subject to them, and 
the consequent character of the respective products. 

Every state of consciousness necessarily implies two 
elements at least : a conscious subject, and an object of 
which he is conscious. In every exercise, for example, of 
the senses, we may distinguish the object seen, heard, 
smelt, touched, tasted, from the subject seeing, hearing, 
smelling, touching, tasting. In every emotion of pleasure 
or of pain, there is a certain affection, agreeable or dis- 
agreeable, existing within me, and of this affection I am 
conscious. In every act of volition, there takes place a 
certain exercise of my will, and I am conscious that it 
takes place. In this point of view, it is not necessary to 
enter on the often disputed question, whether such states 
of consciousness furnish immediate evidence of the ex- 



PROLEGOMENA LOGIGA. 21 

istence of a world external to ourselves. That of which 
I am directly conscious may be an object numerically dis- 
tinct from myself, or it may be a modification of my own 
mind. All that need be insisted upon here is, that there 
is present an individual object, whether thing, act, or state 
of mind, and that we are conscious of such an object as 
existing within or without ourselves. A psychological 
dualism is implied in the very notion of consciousness : 
whether this necessarily involves an ontological dualism, 
is beyond our present purpose to inquire. 1 

But to constitute an act of Thought, more is required 
than the immediate relation of subject to object in con- 
sciousness. Every one of the above states might exist in 
a mind totally incapable of thought. Let us suppose, for 
example, a being, in whose mind every successive state of 
consciousness was forgotten as soon as it had taken place. 
Every individual object might be presented to him pre- 
cisely as it is to us. Animals, men, trees, and stones, 
might be successively placed before his eyes ; pleasure, 
and pain, and anger, and fear, might alternate within him ; 
but, as each departed, he would retain no knowledge that 
it had ever existed, and consequently no power of com- 
parison with similar or dissimilar objects of an earlier or 
later consciousness. He would have no knowledge of 
such objects as referred to separate notions ; he could not 
say, this which I see is a man, or a horse ; this which I 
feel is fear, or anger. He would be deficient in the dis- 
tinctive feature of Thought, the concept or general notion 
resulting from the comparison of objects. Hence arises 

1 This point has been already argued fully and satisfactorily by the 
great modern advocate of Natural Dualism, Sir William Hamilton. The 
reader is referred to his edition of Reid's works, especially to his notes B 
and C, for a masterly dissertation on this important question. 



22 PROLEGOMENA LOGICA. 

the important distinction between Intuitions^ in which 
the object is immediately related to the conscious mind, 
and Thoughts, in which the object is mediately related 
through a concept 2 gained by comparison. The former 
contains two elements only, the subject and the object 
standing in present relation to each other. The latter 
contains three elements, the thinking subject, the object 
about which he thinks, and the concept mediating between 
the two. 3 Thus even the exercise of the senses upon pre- 
sent objects, in the manner in which it is ordinarily per- 
formed by a man of mature faculties, does not consist of 
mere intuition, but is accompanied by an act of thought. 
In mere intuition, all that is simultaneously presented to 
the sense appears as one whole ; but mere intuition does 
not distinguish its several parts from each other under this 

1 Here, and throughout the following pages, the word Intuition is used 
in the extent of the German Anschauung, to include all the products of 
the perceptive (external or internal) and imaginative faculties ; every act 
of consciousness, in short, of which the immediate object is an individual, 
thing, act, or state of mind, presented under the condition of distinct ex- 
istence in space or time. 

2 The revival of this term, unfortunately, till very recently, suffered to 
grow obsolete in philosophy, will need no apology with those who are 
acquainted with the writings of Sir W\ Hamilton. It is absolutely neces- 
sary to distinguish in language between the act of thought and its prod- 
uct, a distinction expressed in Greek by v6-t)ais and yorj/xa, and in the fol- 
loAving remarks by conception and concept. The latter term has been fully 
sanctioned by the usage of French philosophers, as well as of the emi- 
nent Avriter above mentioned. 

3 " In apprehending an individual thing, either itself through sense or its 
representation in the phantasy, we have, in a certain sort, an absolute or 
irrespective cognition, which is justly denominated immediate, by contrast, 
to the moi'e relative and mediate knowledge which, subsequently, we com- 
pass of the same object, when, by a comparative act of the understanding, 
we refer it to a class, that is, think or recognize it, by relation to other 
things, under a certain notion or general term."— Sir W. Hamilton, Beid's 
Works, p. 804. 



PROLEGOMENA LOGICAL 23 

or that notion. I may see at once, in a single panorama, 
a ship upon the sea, an island lying behind it, and the sky 
above it. To mere intuition this is presented only in con- 
fusion, as a single object. To distinguish its constituent 
portions, as sea and land, ship and sky, requires a com- 
parison and classification of them relatively to so many 
separate concepts existing in the mind ; and such classifi- 
cation is an act of Thought. 1 

In every act of Consciousness the ultimate object is an 
individual. But in intuition this object is presented to 
the mind directly, and does not imply the existence, past 
or present, of anything but itself and the mind to which 
it is presented. In thought, on the other hand, the indi- 
vidual is represented by means of a concept, which contains 
certain attributes applicable to other individuals of the 
same kind. 2 This implies that there have been presented 
to the mind prior objects of intuition, originating the con- 
cept or general notion to which subsequent objects are 
referred. Hence arises another important distinction. All 
intuition is direct and presentative ; all thought is indirect 
and representative. 

This distinction necessitates a further remark on the 
characteristic feature of thought, as compared with one 
special class of intuitions. That sensitive perception 

1 Hoffbauer, Logih, § 10. 

2 The terms represent, representation, etc., are, here and throughout the 
present work, used in a wider sense than that to which they are confined 
by Sir W. Hamilton. With that philosopher, the representative faculty 
is synon) r mous with the imagination proper, and the above terms are used 
exclusively with reference to individual objects. See Reid's Works, pp. 895, 
809; Discussions, p. 13. In the following pages the term representation and 
its cognates are extended so as to include the concept, which is representa- 
tive of many individuals, as well as the image, which is representative 
of one. 



24 PROLEGOMENA LOGICA. 

takes place through the medium of a representative idea, 
is a hypothesis which was made more than questionable 
by the philosophy of Reid, and may be regarded as com- 
pletely overthrown by the recent labors of his illustrious 
editor, Sir William Hamilton. But there still remains the 
faculty of Imagination, whose office is the production of 
images representative of the several phenomena of Per- 
ception, 1 internal as well as external. In relation to this 



1 The term Perception requires a few words in explanation. In modern 
philosophy, from Descartes to Reid, this term was used widely, as coex- 
tensive with Apprehension or Consciousness in general, with some minor 
modifications, for an account of which the reader is referred to Sir W. 
Hamilton's Reid, p. 876. By Reid and his followers it was used for the 
consciousness of an external object presented to the mind through the 
organs of sense, as distinguished from Sensation, the consciousness of an 
affection of the subject through the same organs. In this sense they are 
clearly distinguished by M. Royer Collard, Jouffroy's Reid, hi. p. 329. 
"II y a dans 1'operation du toucher sensation et perception tout ensemble: 
changement d'etat ou modification interieure, c'est la sensation; connais- 
sance d'un objet exterieur, c'est la perception." Cf. Reid, Intell. Powers, 
Essay i. ch. i. Stewart, Outlines of Moral Philosophy, § 15. According to 
M. Royer Collard, the senses of smell, hearing, and taste, give rise to sen- 
sations only; touch is in every case a union of sensation and perception; 
while sight holds an intermediate and doubtful position, as informing us 
of the existence of extension, but only in two dimensions of space. Sir 
W. Hamilton, on the other hand, holds that the general consciousness of 
the locality of a sensorial affection ought to be regarded as a Perception 
proper; and, in accordance with this view, he has announced the import- 
ant law, that Sensation and Perception, though always coexistent, are, as 
regards their intensity, always in an inverse ratio to each other. Some 
recent French philosophers, influenced by the union of physiological with 
psychological researches, have employed the term Perception in another 
sense, to denote Sensation with Consciousness, Sensation being extended 
to those affections of the nervous organism of which we are not conscious. 
This occurs in the writings of Maine de Biran, and appears to have misled 
M. Ravaisson into imagining that that philosopher had anticipated the 
above-mentioned law of Sir W. Hamilton. The passage alluded to is 
apparently one in the Essai sur la decomposition de la Pense'c, p. 116, but 



PROLEGOMENA LOGICA. 25 

faculty, the criterion above given as characteristic of 
Thought requires a few words of explanation. 

Imagination, regarded as a product, may be defined, the 
consciousness of an image in the mind resembling and rep- 
resenting an object of intuition. 1 It is thus at the same 
time presentative and representative. It is preservative 
of the image which has its own distinct existence in con- 
sciousness, irrespective of its relation to the object which 
it is supposed to represent. It is representative of the ob- 
ject which that image resembles ; and such resemblance is 
only possible on the condition that the image be, like the 
object, individual. If we try to form in our minds the 

the resemblance is merely verbal. A nearer anticipation may perhaps be 
found in Kant, Anthropologic, § 20. 

In the text, Perception is employed to denote all those states of Con- 
sciousness which are presentative only, not representative. It will thus 
include all intuitions except those of Imagination, and may be divided 
into external or sensitive, and internal; the former corresponding to the 
Perception of Reid. This use of the term, allowance being made for a 
different theory of external Perception, accords with that of Kant. 

1 This is the ordinary psychological sense of Imagination ; however 
variously the term may have been employed in reference to poetry, and 
generally to the philosophy of taste. It corresponds with the definition 
given by Descartes (Meditatio Secunda), " imaginari nihil dliud est quam rei 
corporeal figuram seu imaginem contemplari ; " except that the latter is incor- 
rectly limited to the reproduction of objects of sight only. The beautiful 
lines of Shelley furnish an exact description of imagination relatively to 
two other senses : 

" Music, when soft voices die, 

Vibrates in the memory; 

Odors, when sweet violets sicken, 

Live within the sense they quicken." 

But the operation of the imaginative faculty must not be confined even 
to the general field of sensations. The important question, How many 
presentative faculties has man? will be referred to again. The province 
of imagination will be determined by the answer to this question, as every 
original presentation may be represented in a phantasm. 

3 



26 PROLEGOMENA LOGICA. 

image of a triangle, it must be of some individual figure, 
equilateral, isosceles, or scalene. It is impossible that it 
should be at the same time all of these, or none. It may- 
bear more or less resemblance to the object which it repre- 
sents ; but it can attain resemblance at all only by being, 
like the object itself, individual. I may recall to mind, 
with more or less vividness, the features of an absent 
friend, as I may paint his portrait with more or less ac- 
curacy ; but the likeness in neither case ceases to be the 
individual representation of an individual man. But my 
notion of Man in general can attain universality only 
by surrendering resemblance. It becomes the indifferent 
representative of all mankind only in so far as it has no 
s]3ecial likeness to any one. It is thus not the adequate 
and actual representative of any single object, but an in- 
adequate and potential representative of many ; that is, 
it may in different acts of thought be employed in relation 
to distinct, and in some respects dissimilar, individuals of 
the same class. From this neglect of individual charac- 
teristics arises the first distinguishing feature of a concept ; 
viz. that it cannot in itself be depicted to sense or imagina- 
tion} It is not the sensible image of one object, but an 
intelligible relation between many. 

A second important characteristic of all concepts is, that 
they require to be fixed in a representative sign. This 
characteristic cannot indeed be determined a priori, from 
the mere notion of the concept as universal, but it may be 
proved to a moral certainty a posteriori, by the inability 
of which in practice every man is conscious, of advancing, 
without the aid of symbols, beyond the individual objects 
of sense or imagination. In the presence of several indi- 
viduals of the same species, the eye may observe points of 

1 Cf. Hamilton on Reid, p. 360. 



PROLEGOMENA LOGICA. 27 

similarity between them ; and in this no symbol is needed ; 
but every feature thus observed is the distinct attribute of 
a distinct individual, and, however similar, cannot be re- 
garded as identical. For example: I see lying on the 
table before me a number of shillings of the same coinage. 
Examined severally, the image and superscription of each 
is undistinguishable from that of its fellow ; but, in view- 
ing them side by side, space is a necessary condition of 
my perception ; and the difference of locality is sufficient 
to make them distinct, though similar, individuals. 1 The 
same is the case with any representative image, whether 
in a mirror, in a painting, or in the imagination, waking 
or dreaming. It can only be depicted as occupying a cer- 
tain place ; and thus as an individual and the- representa- 
tive of an individual. It is true that I cannot say that it 
represents this particular coin rather than that ; and con- 
sequently it may be considered as the representative of 
all, successively but not simultaneously. To find a repre- 
sentative which shall embrace all at once, I must divest it 
of the condition of occupying space ; 2 and this, experience 
assures us, can only be done by means of symbols, verbal 
or other, by which the concept* is fixed in the understand- 
ing. Such, for example, is a verbal description of the coin 
in question, which contains a collection of attributes freed 
from the condition of locality, and hence from all resem- 
blance to an object of sense. If we substitute Time for 
Space, the same remarks will be equally applicable to the 
objects of our internal consciousness. Every appetite and 
desire, every affection and volition, as presented, is an in- 

1 On this ground Kant refutes Leibnitz's principle of the identity of in- 
discernables, a principle applicable to concepts, but not to objects of intu- 
ition. 

2 Compare Herbart, Psychdlogie als WissenscJiaft, § 120. Werke, vi. p. 163. 



28 PROLEGOMENA LOGICA. 

dividual state of consciousness, distinguished from every 
other by its relation to a different period of time. States 
in other respects exactly similar may succeed one another 
at regular intervals ; but the hunger which I feel to-day is 
an individual feeling, as numerically distinct from that 
which I felt yesterday, or that which I shall feel to-mor- 
row, as a shilling lying in my pocket is from a similar 
shilling lying at the bank. Whereas my notion of hunger, 
or fear, or volition, is a general concept, having no relation 
to one period of time rather than to another, and, as such, 
requires, like other concepts, a representative sign. 

Language, taking the word in its widest sense, is thus 
indispensable, not merely to the communication, but to 
the formation of Thought. This doctrine is not unfre- 
quently estimated as the correlative or consequent of that 
w T hich derives all knowledge from sensation; an estimate 
apparently warranted by the association of the two theories 
in the philosophy of Condillac. But it would not be 
difficult to show that the ultra-sensational philosophy -is 
that which could most easily dispense with the necessity 
of introducing language at all. Ideas, says Condillac, are 
but transformed sensations ; and his disciple, Destutt de 
Tracy, has carried the doctrine to its fullest development 
in the aphorism penser c'est sentir. But who imagines 
language to be essential to sensation ? Or who does not 
see that the introduction of such an instrument for the 
purpose of transforming our sensations implies the exist- 
ence of a mental power which mere sensation can never 
confer? It is only on the supposition that the concept is 
something distinct from and unlike all the products of the 
senses, that the representative symbol becomes necessary. 
Sensation, imagination, and memory, so far as the latter is 



PROLEGOMENA LOGICA. 29 

distinct from thought, 1 may dispense with its assistance. 
As for the crowning extravagance of Home Tooke, who 
tells us that what are called operations of mind are merely 
operations of language, we have only to ask, what makes 
language operate ? It might as reasonably be maintained 
that a coat is not the work of the tailor, but merely of his 
needle. But it is the perpetual error of the sensational 
school to confound the indispensable condition of a thing 
with the thing itself. Thought is not sensation, though 
the exercise of the senses is a necessary preliminary to that 
of the understanding. Science is not a well-constructed 
language, as the skill of the painter is not indentical with 
the goodness of his brushes and colors ; yet we must 
acknowledge that the power of the artist could neither 
have been acquired nor exhibited, had these necessary 
implements been withheld. 

The above view of the relation of thought to language 
is sometimes met by the following dilemma. " Language, 
you say, is essential to thought ; yet language itself, if not 
of divine origin, must have been thought out by man. 
You must, therefore, be prepared to defend in its utmost 
rigor the hypothesis of a supernatural origin of speech ; or 
you must allow that its inventor, at least, was a man 
capable of thinking without its aid." 2 To solve this 

1 So far, namely, as it corresponds to the fivfifiy, not to the avdfxvrja-is 
of Aristotle. The neglect of this distinction led Condillac to deny that 
brutes have any memory, since they are destitute of language. Aristotle, 
with more accuracy, allows that memory is common to men and brutes, 
but reminiscence peculiar to the former. See De Memoria, ch. 2, § 25. 

2 See Rousseau, Discours sur Vorigine de Vine'galite parmi les hommes, 
Premiere Partie. " Franchissons pour un moment l'espace immense qui 
dut se trouver entre le pur etat de nature et le besoin des langues ; et cher- 
chons, en les supposant necessaires, comment elles purent commencer a 
s'e'tablir. Nouvelle difficulte pire encore que la precedente: car si les 

3* 



30 PROLEGOMENA LOGICA. 

dilemma, we need not call in aid the curious hypothesis 
of Condillac, who held that the dependence of thought 
on sensation (and by implication on- language) was a 
consequence of the fall of Adam ; we need only observe 
what actually takes place in the formation of language 
and thought among- ourselves. To the child learning to 
speak, words are not the signs of thoughts, but of intuitions; 
the words man and horse do not represent a collection 
of attributes, but are only the name of the individual now 
before him. It is not until the name has been successively 
appropriated to various individuals, that reflection begins 
to inquire into the common features of the class. 1 Lan- 
guage, therefore, as taught to the infant, is chronologically 
prior to thought and posterior to sensation. In inquiring 
how far the same process can account for the invention 
of language, which now takes place in the learning it, the 
real question at issue is simply this : Is the act of giving 
names to individual objects of sense a thing so completely 
beyond the power of man, created in the full maturity 
of his faculties, that we must suppose a divine Instructor 
performing precisely the same ofiice as is now performed 
for the infant by his mother or his nurse; teaching him, 
that is, to associate this sound with this sight? This 
question may be answered affirmatively or negatively, but 
in either case it has nothing to do with the relation of 
language to thought, properly so called. 2 

hommes ont eu besoin de la parole pour apprendre a penser, ils ont cu 
bien plus besoin encore de savoir penser pour trouver l'art de la parole." 

1 See Adam Smith's Considerations concerning ike first Formation of Lan- 
guages, appended to his Theory of Moral Sentiments. 

2 On this subject, the following remarks of Maine de Biran are well 
worthy of attention: "Pour que ces premiers signes donnes deviennent 
quelque chose pour l'individu qui s'en sert, il faut qu'il les institue lui- 
meme une seconde fois par son activite propre, ou qu'il y attache un sens. 



PROLEGOMENA LOGICA. 31 

In relation to this question, the reader must be careful 
not to confuse Language with Articulations. The case 
of the deaf and dumb, so often quoted as an instance 
of thought without language, is in this respect utterly 
irrelevant. The education of these persons consists in the 
substitution of a system of signs addressed to the eye 
or the hand in the place of one addressed to the ear. 
This system performs precisely the same office in relation 
to them that speech performs in the ordinary mental 
development of children : it constitutes, in fact, their 
language. They are thus in no respect an exceptional 
case ; and the whole question has to be considered on 
general, not on special data. I cannot perceive any other 
man's thoughts as they pass in his mind: I can only infer 
their existence by perceptible signs ; and this presupposes 
an established system of communication. The only valid 
method of investigating the relation between thought and 
speech is to examine the only instances in which both 

Ceux qui pensent que l'homme n'eut pu jamais inventer le langage, si Dieu 
meme ne le lui eut donne' ou revele, ne me semblent pas bien entendre la 
question de 1'institution du langage: ils confondent sans cesse le fond avec 
les formes. Suppose que Dieu eut donne a l'homme une langue toute 
faite ou un systeme parfait de signes articules ou ecrits propres a expri- 
mer toutes ses idees : il s'agissait toujours pour l'homme, d'attribuer a 
chaque signe sa valeur ou son sens propre, c'est-a-dire d'instituerveritable- 
ment ce signe avec une intention et dans un but concu par l'etre intelli- 
gent, de meme que l'enfant institue les premiers signes quand il trans- 
forme les cris qui lui sont donnes par la nature en veritables signes de 
reclame. 

"La diffieulte du probleme psychologique, qui consiste a de'terminer les 
faeulte's qui ont du concourir a l'institution du premier langage, subsiste 
done la meme, soit que les signes qui sont la forme et comme le mate'- 
riel de ce langage aicnt ete' donnes ou reveles par la supreme intelligence, 
soit qu'ils aient ete invente's par l'homme ou suggeres par les idees ou les 
sentimens dont ils sont 1'expression." — Nouvelles Considerations sur les rap- 
ports du physique et du moral de l'homme, p. 93. 



32 PROLEGOMENA LOGICA. 

elements are presented, the operations of my own con- 
sciousness. Accepting what is there given in combination, 
I must endeavor by analysis to ascertain how much of 
the compound phenomenon is necessary, and how much 
accidental. 

The concept, as thus described, is the characteristic 
feature of Thought proper, as distinguished from other 
facts of consciousness : and the thinking process may be 
adequately defined as the act of knowing or judging of 
things by means of concepts} It remains to inquire what, 
according to this definition, must be the limits within 
which Thought is operative, and what, consequently, will 
be the distinguishing character of its laws. 

Thought is only operative within the field of possible 
experience; i. e., upon such objects as can be presented in 
an actual intuition or represented in an imaginary one. 
For the concept is the result of data furnished by intui- 
tion ; and its legitimacy, as an object of thought, must be 
tested by reference to the same data. It is true that the 
concept itself, as such, cannot be presented intuitively ; 
but it must contain no attribute which is incompatible 
with the intuitive presentation of its object. The concept 
is not itself individual, but it must comprehend such 
attributes as are capable of individualization, such as can 
coexist in an object of intuition. The notion of a triangle, 



1 " Der Verstand iiberhaupt kann als ein Vermogen zu urtheilen vor- 
gestellt Averden. Denn er ist nach dem Obigen ein Vermogen zu denken. 
Denken ist das Erkenntniss durcli Begriffe." Kant, Kritik der rein. Vem. 
(p. 70). An exact adherent of Kant would regard the definition given in 
the text as tautological; for with him the provinces of Thought and Judg- 
ment are coextensive, and all judgment requires concepts. But as in the 
following remarks the province of judgment is extended beyond that of 
thought, the limitation becomes necessary. 



PROLEGOMENA LOGICA. 83 

as a rectilinear figure of three sides, does not itself contain 
the attributes of equilateral, isosceles, or scalene ; but it is 
capable of being combined with any one of the three in a 
perceived or imagined figure. But a rectilinear figure of 
two sides is, by the application of the same test, shown 
to be no concept at all. So long as we merely unite the 
attributes in speech, without attempting to combine them 
in an individual object, we may not be aware that we are 
talking nonsense ; the attempt to imagine the figure shows 
at once the incompatibility of the attributes. This, then, 
is the criterion of positive thinking. A form of words, 
uniting attributes not presentable in an intuition, is not 
the sign of a thought, but of the negation of all thinking. 
Conception must thus be carefully distinguished, as well 
from mere imagination, as from a mere understanding 
of the meaning of words. 1 Combinations of attributes 
logically impossible may be expressed in language per- 
fectly intelligible. There is no difficulty in understanding 
the meaning of the phrase bilinear figure, or iron-gold. 
The language is intelligible, though the object is incon- 
ceivable. On the other hand, though all conception 
implies imagination, yet all imagination does not imply 
conception. To have a valid conception of a horse, I 
must not only know the meaning of the several attributes 
constituting the definition of the animal, but I must also 
be able to combine those attributes in a representative 



1 These have been confounded by others besides Reid. Thus Aldrich, 
after defining Simple Apprehension as nudus rei conceptus intellectivus, pro- 
ceeds : " Si quis dixerit Triangulum cequilaterum esse cequiavgulum, possum 
Apprehensione Simplici incomplexa intelligere quid sibi velint singula 
Orationis hujus vocabula." Apprehension in this sense is not a logical 
process at all, and is not governed by any of the laws of logical thinking. 
— Cf. Hamilton on Reid, p. 377. 



34 PROLEGOMENA LOGICA. 

image; that is, to individualize them. This, however, is 
not mere imagination, it is imagination relatively to a 
concept. I not only see as it were the image with the 
mind's eye, but I also think of it as a horse, as possessing 
the attributes of a given concept, and .called by a name 
expressive of them. But mere imagination is possible 
without any such relation. Without any effort to recall 
an object by means of its distinctive attributes, I may 
be passively conscious of the continuance, in a weaker 
state, of a sensible or otherwise intuitive impression, when 
the object which gave rise to it is no longer present. This 
is the Imagination which is described by Aristotle as a 
hind of toeak sensation, 1 and as sensitive imagination? 
When coupled with a consciousness of the past existence 
of the impression which it represents, it forms the Memory, 
as distinguished from the Reminiscence, of Aristotle. 3 This 
kind of imagination does not in itself involve a distinction 
or comparison of presentations : it is compatible with an 
ignorance or forgetfulness of the existence of any presen- 
tations, save the one represented by the image. Concep- 
tion, on the other hand, in its lowest degree, implies at 
least a comparison and distinction of this from that. 
When exhibited, as for its ultimate verification it must 
be, in the construction of an individual image answering 
to the general notion, it is still an act of thought, rather 
than of intuition; and when coupled with the conscious 
effort to recall v a past impression, it answers in some 
decree to the Reminiscence of Aristotle. 4 



1 BM. I. 11. 2 j) e Anima, III. 11. 3 De Memoria, c. 1. 

4 " The Understanding, thought proper, notion, concept, etc., may coin- 
cide or not with Imagination, representation proper, image, etc. The two 
faculties do not coincide in a general notion; for we cannot represent Man 
or Horse in an actual image without individualizing the universal; and 



PROLEGOMENA LOGICA. 35 

Conception, where it does not coincide with imagination, 
implies imagination as the test of its validity. To form 
the notion of a class as distinguished from an individual, I 
must emancipate the attributes of which I am conscious 
from their connection with a definite time and place, and 
this, as has been already observed, requires the intervention 
of language. The consciousness of a general notion is thus 
an instance of symbolical as distinguished from intuitive 
knowledge; 1 and the act of Conception, viewed apart from 
Imagination, could only consist in the enumeration, by 
means of verbal or other symbols, of the different parts 
constituting a given notion. 2 But the symbol, though in- 

thus contradiction emerges. But in the individual, say Socrates or Bu- 
cephalus, they do coincide ; for I see no valid ground why we should not 
think, in the strict sense of the word, or conceive the individuals which we 
represent." — Sir W. Hamilton, Discussions, p. 13. The Reminiscence of 
Aristotle will include this kind of imagination under it, as the last step of 
the process. 

1 This distinction is due to Leibnitz. See his Meditationes de Cognitione, 
Veritate, et Ideis, Opera, ed. Erdmann, p. 79. 

2 " In cognitione symbolica prima mentis operatio absolvitur recensione vocab- 
ulorum, vel aliorum signorum, quibus ea indigitantur quoz notionem rei distinc- 
tam ingrediuntur. Etenim in cognitione symbolica tantummodo verbis 
enunciamus quae in ideis continentur, vel aliis signis eadem repraesenta- 
mus, ideas vero ipsas verbis aut signis aliis indigitatas non intuemur. 
Quare cum in cognitione intuitiva prima mentis operatio absolvatur si 
attentionem successive in idea rei ad ea dirigimus quae notionem distinc- 
tam generis vel speciei ingrediuntur, singula autem haec enunciabilia sint, 
adeoque vocabulis vel signis aliis indigitari possint; in cognitione symbol- 
ica prima mentis operatio absolvi debet recensione vocabulorum, vel rep- 
raesentatione aliorum signorum, quibus ea denotantur, quae notionem rei 
distinctam ingrediuntur. Ita prima mentis operatio in cognitione symbol- 
ica arboris absolvitur, si dicimus vegitabile, quod ex trunco, ramis, surcu- 
lis et foliis constat; etenim sigillatim i*ecensemus verba quibus ea indigi- 
tantur quae in arboribus tanquam communia distinguimus, consequenter 
quae notionem arboris in genere, quatenus distincta est, ingrediuntur. 
ISTon autem jam nobis quaestio est, utrum notio distincta sit completa 



6b PROLEGOMENA LOGICA. 

dispensable as an instrument of thought, lends itself with 
equal facility to every combination, and thus furnishes no 
criterion by which we can distinguish between sense and 
nonsense, between the conceivable and the inconceivable. 
A round square, or a bilinear figure, is, as a form of 
speech, quite as possible as a straight line, or an equilateral 
triangle. The mere juxtaposition of words does not indi- 
cate the possibility or impossibility of the corresponding 
notion, until we attempt to construct in imagination an in- 
dividual object in accordance with it. Till this criterion is 
applied, the act of conception is rather a substitute for 
consciousness than a mode of consciousness itself. The 
sign is substituted for the thing signified ; a step which 
considerably facilitates the performance of complex opera- 
tions of thought, but in the same proportion endangers the 
logical accuracy of each successive step ; since we do not, 
in each, stop to verify our signs. Words, as thus employed, 
resemble algebraical symbols, which, during the process of 
a long calculation, we combine in various relations to each 
other, without at the moment thinking of the original sig- 
nification assigned to each. But those who, on this ac- 
count, would reduce the whole of thought to an algebraical 
computation, overlook the most important feature, the ver- 
ification, namely, of the result, according to the logical 
conditions of conception, after the algebraical process is 
finished. It may be convenient, in the course of a compli- 
cated reasoning, to assume the logical accuracy of the sub- 



atquc detcrminata, atque oratione ista talis notio significetuv, ut lisec defi- 
nhionis loco inservire possit. Sufficit enim hie ea sigillatim enunciari 
quae mente ab idea rei separantur, dum distincte nobis genus vel speciem 
reprsesentare conamur. Pendet enim cognitio symbolica ab intuitiva, 
quam supponit et ad quam rcfertur. Quicquid igitur huic deest, idem 
etiam illi deesse debet." — Wolf, Psychologia Empirica, § 328. 



PROLEGOMENA LOGICA. 37 

ordinate parts, and to employ their respective symbols on 
this assumption. But what the concept gains in flexibility 
it loses in distinctness ; and the logical and algebraical 
perfections are thus in an inverse ratio to each other. It 
therefore becomes necessary, at the end of the process, to 
submit the result to the logical test, to which each step has 
been tacitly supposed to conform ; that of the possible co- 
existence of the several attributes in an individual object. 1 

The above remarks will necessitate some modification 
of the doctrines ordinarily taught in logical treatises con- 
cerning general notions, or, as they are commonly though 
not very happily called, abstract ideas. We are told that 
the mind examines a number of individual objects, agree- 
ing in some features and differing in others, that it sepa- 
rates the points in which they agree from those in which 
they differ, and makes, of the former only, an abstract idea 
or general notion, which is indifferently applicable to all 
the individuals from which it was derived, and by virtue 
of which they are all called by a common name. 

The reality of this process of Abstraction, 2 and of the 

1 "Plerumque, prresertim in analysi longiore, non totam simul naturam 
rei intuemur, sed rerum loco signis utimur, quorum explicationem in pras- 
senti aliqua cogitatione compendii causa solemus prsetermittere, scientes, 
aut credentes nos earn habere in potestate: ita cum chiliogonum, seu poly- 
gonum mille requalium laterum cogito, non semper naturam lateris, et 
ajqualitatis, et millenarii (seu cubi a denario) considero, sed vocabulis istis 
(quorum sensu obscure saltern, atque imperfecte menti obversatur) in 
animo utor loco idearum, quas de iis habeo, quoniam memini me signifiea- 
tionern istorum vocabulorum habere, explicationem autem nunc judico 
necessarian! non esse; qualem cogitationem ceecam, vel etiam symbolicam 
appellare solco, qua et in Algebra, et in Arithmetical utimur, imo fere 
ubique." — Leibnitz, Meditationes de Cognitione, Veritate et Ideis. 

2 Drobisch observes that the term Abstraction is used sometimes in a 
psychological, sometimes in a logical sense. In the former, we are said 
to abstract the attention from certain distinctive features of objects pre- 

4 



38 PROLEGOMENA LOGICA. 

idea to which it is supposed to give rise, has been matter 
of considerable controversy among modern philosophers. 
Bishop Berkeley, and subsequently Hume, denied alto- 
gether the possibility of such an operation, on the following 
grounds. The general idea of a triangle, it was argued by 
Locke, 1 is an imperfect idea, wherein parts of several differ- 
ent and inconsistent ideas are put together. As limited to 
no particular kind of triangle, but comprehending all, it 
must be neither oblique, nor rectangle, neither equilateral, 
equicrural, nor scalene, but all and none of these at once. 
The abstract idea, as thus described, Berkeley easily per- 
ceived to be self-contradictory, and the doctrine suicidal. 
" I have a faculty," he says, " of imagining or representing 
to myself the ideas of those particular things I have per- 
ceived, and of variously compounding and dividing them. 
I can imagine a man with two heads, or the upper parts of 
a man joined to the body of a horse. I can consider the 
hand, the eye, the nose, each by itself, abstracted or sepa- 
rated from the rest of the body. But then, whatever hand 
or eye I imagine, it must have some particular shape and 
color. Likewise the idea of man that I frame to myself, 
must be either of a white, or a black, or a tawny, a straight 
or a crooked, a tall or a low, or a middle-sized man. To 
be plain, I own myself able to abstract in one sense, as 
when I consider some particular parts or qualities separa- 
ted from others, with which though they are united in 
some object, yet it is possible they may really exist without 



sented (abstrahere a differentiis). In the latter, we are said to abstract cer- 
tain portions of a given concept from the remainder (abstrahere differentias). 
The former sense must be understood here, where we are considering the 
mental process by which concepts are formed. To the latter, as a con- 
scious process of thought, the following remarks do not apply. 
1 Essay, book iv.'ch. 7, § 9. 



PROLEGOMENA LOGICA. 39 

them. But I deny that I can abstract one from another, 
or conceive separately, those qualities which it is impossi- 
ble should exist so separated; or that I can frame a gen- 
eral notion by abstracting from particulars in the manner 
aforesaid." x 

" It is, I know," continues the Bishop, " a point much in- 
sisted on, that all knowledge and demonstration are about 
universal notions, to which I fully agree : but then it doth 
not appear to me that those notions are formed by abstrac- 
tion in the manner premised ; universality, so far as I can 
comj^rehend, not consisting in the absolute, positive nature 
or conception of anything, but in the relation it bears to 
the particulars signified or represented by it : by virtue 
whereof it is that things, names, or notions, being in their 
own nature particular, are rendered universal. Thus when 
I demonstrate any proposition concerning triangles, it is to 
be supposed that I have in view the universal idea of a 
triangle ; which ought not to be understood as if I could 
frame an idea, of a triangle which was neither equilateral, 
nor scalene, nor equicrural. But only that the particular 
triangle I consider, whether of this or that sort it matters 
not, doth equally stand for and rejDresent all rectilinear tri- 
angles whatever, and is in that sense universal 

Though the idea I have in view whilst I make the demon- 
stration be, for instance, that of an isosceles rectangular 
triangle, whose sides are of a determinate length, I may 
nevertheless be certain it extends to all other rectilinear 
triangles, of w T hat sort or bigness soever; and that, be- 
cause neither the right angle, nor the equality, nor deter- 
minate length of the sides, are at all concerned in the 
demonstration. It is true, the diagram I have in view in- 
cludes all these particulars ; but then there is not the least 

1 Principles of Human Knowledge, Introduction, § x. 



40 PROLEGOMENA. LOGICA. 

mention made of them in the proof of the proposition. . . . 
And here it must be acknowledged, that a man may con- 
sider a figure merely as triangular, without attending to 
the particular qualities of the angles or relations of the 
sides. So. far he may abstract : but this will never prove 
that he can frame an abstract general inconsistent idea of 
a triangle." 1 On the other hand, it was argued by Reid, 
that if a man may consider a figure simply as triangular, 
without attending to the particular qualities of the angles 
or relations of the sides, he must have some conception of 
this object of his consideration ; for no man can consider a 
thing which he does not conceive. He has a conception, 
therefore, of a triangular figure, merely as such ; and this 
is all that is meant by an abstract general conception of a 
triangle. 2 

In this controversy, the question has been needlessly 
confused by the vague and inaccurate use of terms. Idea 
has been indifferently employed, by modern philosophers, 
to denote the object of thought, of imagination, and even 
(under the representative hypothesis) of perception. 3 Con- 
ception, again, has not been sufficiently distinguished, on 
the one side, from imagination, and, on the other, from a 
mere understanding of the meaning of words ; and too 
little attention has been paid to the office of language, 
both as a substitute for consciousness, and as contributing 
to the distinctness of consciousness itself. It is not strictly 

1 Principles, of Human Knowledge, Introduction, §§ xv. xvi. 

2 Intellectual Powers, Essay v. ch. 6. 

3 As it is sometimes convenient to have a general term indifferently 
applicable to any object of internal consciousness, I have in the present 
work occasionally availed myself in this extent of the term Idea, reject- 
ing, however, the representative idea of perception. But the term has 
been avoided wherever it is necessary to distinguish between two different 
states of consciousness. 



PROLEGOMENA LOGICA. 41 

correct to say that the individual alone is perceived first, 
and the general notion formed from it by abstraction ; for, 
without the assistance of the general notion, the indi- 
viduals themselves and their several parts could not be 
distinguished from each other. If I am to form. a general 
notion of man by examining the individuals Peter, James, 
and John, and separating the accidents in which they 
differ from the essential points in which they agree, it is 
clear that I must previously have formed general notions 
of the parts thus separated from each other. In order to 
separate, by an act of thought, the figure common to a 
number of men from the accidents of stature, complexion, 
etc., peculiar to each, I must first be able to form distinct 
notions of the human figure on the one side, and of the 
several statures, complexions, etc., on the other. Abstrac- 
tion thus presupposes conception, no less than conception 
presupposes abstraction ; and we have still to learn how 
either process can be a preliminary condition to the other. 
The fact is, that our earliest consciousness is neither 
of the individual discerned as an individual, nor of the 
universal discerned as an universal, but of a confused 
mixture of the two, which it requires a further develop- 
ment of thought to analyze into the one or the other. 1 
Whatever we perceive occupies a definite position in time 
and space ; it is seen now and here; so far it is an indi- 
vidual. But position in time and space does not constitute 
a mark by which this individual can be distinguished from 
that; I cannot by these relations alone determine whether 
the object seen now and here is or is not the same indi- 
vidual that was formerly seen elsewhere. To discern the 
individual as such or the universal as such, I must by an 

1 See Sir W. Hamilton's Lectures on Metaphysics, p. 497. 

4# 



42 PROLEGOMENA LOGICA. 

act of thought discern certain attributes as characteristic 
of one, and certain others as common to many ; and this 
power of discernment is gradually imparted to each of us 
in practice by the use of language, in which our earliest 
abstractions are given to us already made. In this gradual 
formation of distinct thought from confused intuition, it 
may in one sense indeed be said that our knowledge of the 
class is prior to that of the individual. For resemblances 
are noticed earlier than differences; 1 and the names dis- 
tinctive of individuals are at first associated only with 
their general features. "Children," says Aristotle, " at first 
call all men father, and all women mother, but afterwards 
they distinguish one person from another." 2 By degrees 
the individual attributes are discerned and separated from 
the generic ; but in the first instance the name is applied 
to different objects before we have learned to analyze the 
growing powers of speech and thought, to ask what we 
mean by each several use of this or that appellation, and 
to correct and fix the signification of words at first used 
vaguely and obscurely. Such is the actual service per- 
formed by language in the education of mankind under 
the existing conditions of social intercourse. What was 
the origin of language itself, and how far the same descrip- 
tion will apply to the mental development of the first man, 
is matter rather of ingenious conjecture than of scientific 
explanation. 

Berkeley, therefore, was clearly right in denying the 
existence of any such process of Abstraction as that 
described by Locke. The error of the latter consisted 

1 A contrary theory on this point is the source of most of the difficulties 
which Rousseau professes to find in accounting for the origin of general 
language from the names given to individuals. 

2 Phys. Ausc. I. 1. 



PROLEGOMENA LOGICA. 43 

in regarding Abstraction as a positive act of thought, 
instead of the mere negation of thought. Abstraction is 
nothing more than non-attention to certain parts of an 
object: we do not positively think of a triangle as neither 
equilateral, isosceles, nor scalene ; but we think of the 
figure as composed of three sides, without asking the 
question whether those sides are equal or unequal. But, 
on the other hand, Berkeley, in maintaining that all 
notions are in their own nature particular, has overlooked 
the fact that thought, and language as the instrument 
of thought, is necessary to distinguish the particular as 
particular, no less than the universal as universal ; and 
that we are thus enabled, partially in intuitive and wholly 
in symbolical cognition, to discern generic attributes, and 
to constitute them an object of conception, without being 
conscious of the particulars by which they are accom- 
panied. Berkeley is right in denying that we can imagine 
the universal entirely apart from the particular, but, owing 
to the vague significance of the word idea, he seems to 
speak of imagination as if it were coextensive with con- 
ception. In symbolical cognition, the latter process may 
be carried on apart from the former, subject, however, as 
has been already observed, to the condition of being 
tested as valid or invalid by the power of imagining a 
corresponding object. This distinction has been clearly 
indicated by Berkeley in another of his works; 1 and perhaps 
his whole discussion needs only a more exact distinction 
between the perception of individuals in time and space 
and the recognition of them by their peculiar attributes, to 
render it philosophically unexceptionable. 

In speaking of Imagination as the test of Conception, 
we do not accede to the ultra-sensationalism of Condillac, 

1 Minute Philosopher, Dial. vii. § 8. 



44 PROLEGOMENA LOGICA. 

nor even to the modified doctrine of Laromiguiere, who 
derives from the senses the whole matter of our knowl- 
edge. Individualize your concepts, does not mean sensa- 
tionalize them, unless the senses are the only sources of 
presentation. If I am immediately conscious, for example, 
of an exercise of will, as an individual act taking place 
within me, the phenomena of volition become a distinct 
class of presentations, coordinate with, not subordinate to, 
those of the senses, and capable, like them, of being repre- 
sented by the imagination and thought upon by the under- 
standing. If I am conscious of emotions of joy or sorrow, 
of anger or fear, existing as present individual states of 
mind, distinct from sensible impressions, these, in like 
manner, must be considered as data for thought, furnished 
by intuition. If, on the perception of certain individual 
acts performed by myself or by another, I am immediately 
conscious of an idea of right or wrong • I have again a 
distinct class of intuitions, simple and undefinable, the 
laws and common features of which may furnish matter 
of further reflection, but the existence of which, as indi- 
vidual facts, is the indispensable condition of all moral 
speculation. 

The possibility, therefore, of any branch of scientific in- 
quiry depends upon the psychological question, Hoio many 
presentative faculties has man ? 1 Every such faculty may 

1 In speaking of the human mind as possessing a plurality of faculties, 
it is perhaps hardly necessary to protest against the misinterpretation of 
this language, as if it implied that these faculties were distinct and inde- 
pendent portions of the mind, like the separate members of the body. 
Sir W. Hamilton {Lectures on Metaphysics, Lect. xx.) has shown that the 
contrar} 7- opinion has been the one generally prevalent, that the vast ma- 
jority of philosophers have either openly asserted or silently assumed 
that the faculties of mind are nothing more than modes in which the sim- 
ple indivisible principle of thought may act and exist. As thus explained, 



PROLEGOMENA LOGICA. 45 

furnish distinct materials for thought. Physical Science 
is possible, if the senses present us with material phenom- 
ena whose relations and laws thought may investigate. 
Moral Science is possible, if we are presented with the 
fact of moral approbation and disapprobation of this or 
that action, in itself, and for its own sake ; and the ques- 
tion for thought to investigate is, Whence do these feelings 
arise, and on what laws are they dependent ? iEsthetical 
Science is again possible as a distinct branch of inquiry, 
if the emotions arising from the contemplation of beauty 
in the works of nature or of art can be shown to be dis- 
tinct from any communicated by their mere relation to 
the senses. And Metaphysics must submit to the same 
criterion. Rational Cosmology and Rational Psychology 
are possible, only if Matter and Mind, as distinct from 
their several phenomena, can be shown to be in any way 
presented, as the object of an immediate intuition. 

This distinction between the presentations of intuition 
and the representations of thought, which is thus the key 
to all the most valuable applications of Psychology, is 
intimated with more or less accuracy in the writings of 
several modern philosophers. The often -quoted passage 
of Locke, in which the operations of thought are com- 

the term is unobjectionable. It may be that in mental, as in physical 
mechanics, we know force only from its effects; but the consciousness 
of distinct effects will then form the real basis of Psychology. The fac- 
ulties may then be retained as a convenient method of classification, pro- 
vided the language is properly explained, and no more is attributed to 
them than is warranted by consciousness. The same consciousness which 
tells me that seeing is distinct from hearing, tells me also that volition 
is distinct from both; and to speak of the faculty of will does not neces- 
sarily imply more than the consciousness of a distinct class of mental 
phenomena. No one but an advocate of the grossest materialism could 
understand such an expression as implying numerically distinct organs 
of mind, as of body. 



46 PROLEGOMENA LOGIC A. 

pared to the productions of art, furnishes in this respect, 
when understood in its proper latitude, an unexceptiona- 
ble description of the respective provinces of the intuitive 
and discursive faculties. " It is not in the power of the 
most exalted wit, or enlarged understanding, by any quick- 
ness or variety of thought, to invent or frame one new 
simple idea in the mind. The dominion of man, in this 
little world of his own understanding, being much the 
same as it is in the great world of visible things ; wherein 
his power, however managed by art and skill, reaches no 
farther than to compound or divide the materials that are 
made to his hand ; but can do nothing towards the making 
the least particle of new matter, or destroying one atom 
of what is already in being." 1 The Ideas of Sensation 
and Ideas of Reflection of the same philosopher, however 
unfortunate may be the original choice of terms, and how- 
ever inconsistent their subsequent employment, point cor- 
rectly enough to the two great sources of external and 
internal intuition. 2 A further step in accuracy is gained 
in the Impressions and Ideas of Hume, though the dis- 
tinction loses most of its value in his hands by the absurd 
ground of distinction which he has laid down between 
them, and by the unfortunate metaphor which declares 
every idea to be an image of an impression. 3 Kant, who 

1 Essay, b. ii. cli. 2 § 2. 

2 Reflection, in consistency with etymology, ought to have been limited 
to the operations of thought; in which sense we can reflect upon sensible 
objects as upon all other things. Locke only escapes from Reid's criti- 
cism on this point by using reflection improperly, as Stewart has ob- 
served, as synonymous with [internal] consciousness. This use of the 
term, howcA'er, is not peculiar to Locke. See Sir W. Hamilton's Lectures 
on Metaphysics, pp. 162, 406. 

3 According to Hume, Ideas and Impressions differ from each other only 
in their different degrees of force and vivacity; and belief he defines as 



PROLEGOMENA LOGICA. 47 

took up the discussion where Hume left it, with the ad- 
vantage of a new philosophical language, unencumbered 
with the associations of earlier systems, is the earliest phi- 
losopher whose writings have disentangled the confusion 
universally following on the use of the term idea, and 
exhibited this most important distinction with any degree 
of accuracy and precision. 1 It is one of the most valuable 
principles of the Critical Philosophy, that the understand- 
ing has no power of intuition ; a principle which does not, 
however, necessitate the adoption of the Kantian division 
of the mental faculties, nor even the determination of the 
question, whether the mind possesses numerically distinct 
faculties at all. It simply means, that the act of Thought 
cannot create its own object : that, being mediate and rep- 
resentative, it requires to be based on an immediate and 
presentative fact of consciousness. 

It cannot therefore be maintained that the senses are 
the sole criteria of truth and of reality, unless we assume, 

" a lively idea associated with a present impression;" a doctrine which 
almost justifies the sarcastic application of Reid, "it will follow, that the 
idea of a lion is a lion of less strength and vivacity. And hence may 
arise a very important question, whether the idea of a lion may not tear 
in pieces and devour the ideas of sheep, oxen, and horses, and even of 
men, women, and children." 

1 In this respect, nothing can be more unfair than Stewart's sneers at 
the obscurity and new technical language of Kant. The philosophical 
terms of English and French writers are derived from the same source, 
and subject to the same varieties of application. The purism of German 
writers has given to all subsequent thinkers the inestimable advantage of 
contemplating the same thoughts under a new phraseology, and with new 
associations of etymology and metaphor; an advantage which no one has 
appreciated more highly, or explained more happily, than Stewart himself, 
on another occasion. As it is impossible to comply exactly with the pre- 
cept of Locke, to judge of ideas in themselves, their names being wholly 
laid aside, the next best course is, to examine them, as far as possible, 
through the medium of two independent languages. 



48 PROLEGOMENA LOGICA. 

in defiance of all consciousness, that there exist no im- 
mediate mental phenomena, but those communicated by 
sensation. Any one presentation is as true and as real as 
any other. Falsehood and unreality can only begin with 
thought. The immediate judgment of presentation, that 
I am at this moment conscious of a certain object, is 
equally true as regards any class of presentations. Un- 
reality, in this case, can only consist in the distinctness of 
one class of presentations from another, which latter we 
have arbitrarily selected as the test of reality ; and false- 
hood, in the assertion of the identity of distinct classes, or 
of the distinctness of identical ones. But such a selec- 
tion or assertion involves an act of thought ; it is a 
judgment concerning intuitions as classified under certain 
concepts. If I choose arbitrarily to select the senses as 
the sole test of reality, the phantasms of imagination are 
so far unreal ; but their unreality implies no more than 
that they are not perceived by the senses. If I say, "A 
centaur exists as an image in my mind, therefore it exists 
in nature," the assertion is false, because, by an act of 
thought, I judge that to be an object of possible sense, 
which is only given to me as an object of imagination : 
its reality in relation to the latter faculty remains un- 
disturbed. 

This view of the reality of all presentations, as such, 
could not indeed be consistently held by the advocates of 
a representative theory of perception. If, in all intuition, 
I am immediately conscious only of certain ideas or modi- 
fications of my own mind, I am reduced to the alternative, 
either of disbelieving the existence of an external world 
altogether, or of drawing a distinction between such ideas 
as are representative and indicate the existence of objects 
without my mind, and such as are purely imaginary and 



PROLEGOMENA LOGICA. 49 

have no objective reality corresponding. 1 The former will 
then be distinguished as real, the latter as unreal presenta- 
tions. But if, in perception, I am immediately and pre- 
sentatively conscious of a non-ego (and such is the soundest 
view, both in common sense and in philosophy), the repre- 
sentative idea and its supposed claim to superior reality 
vanishes altogether. Every presentation is real in itself, 
some as immediately informing me of the existence of 
states of my own mind, others as immediately informing 
me of the existence of objects without ; and my judgment 
about each is equally true when I assert it to be what it 
is, and equally false when I assert it to be what it is not. 
In this respect, the philosophers of the school of Common 
Sense have not always consistently adhered to their fun- 
damental principle, in the distinction which they have 
drawn between perception and imagination. 2 

But though it is not true that the whole matter of 
knowledge is furnished by the senses, it cannot be denied, 
that it is entirely furnished by the presentative faculties. 
And this may throw some light on a distinction, concern- 
ing which there frequently exists considerable confusion, 
the distinction between what are, vaguely enough, termed 
positive and negative ideas. A positive intuition is one 
which has been presented to us in actual consciousness, 
real or imaginary : a positive concept is one whose com- 
ponent parts are capable of being so presented in combi- 
nation. A negative concept, on the other hand, which 
is in fact no concept at all, is the attempt to realize in 

1 See Locke, Essay, b. iv. ch. 4, §§ 3—12. 

2 See Reid, Inquiry, ch. ii. § 3, and the antagonist remarks of Stewart, 
Elements, vol. i. ch. 3. Both discussions might have been cleared of some 
confusion by determining accurately what is meant by reality in Presen- 
tations. 

5 



50 PROLEGOMENA LOGICA. 

thought those combinations of attributes of which no 
corresponding intuition is possible. The inability may be 
absolute or relative, owing to the general limitations of all 
human consciousness, or to peculiar deficiencies in the 
experience of this or that individual. Thus a blind man 
may be said to have a negative idea of color, when he 
attempts to supply the defects of his experience by anal- 
ogy from other sensations; as in the case mentioned by 
Locke, of the man who supposed the color of scarlet to 
resemble the sound of a trumpet. 1 But in like manner 
any man, though in the full j>ossession of his faculties, can 
only negatively conceive those simple ideas 2 which have 
never been actually presented in their proper intuition. 
The nature of the presentation will of course depend upon 
the faculty to which that class of intuitions belongs. If I 
have never seen objects of any other color than white and. 
red, I have a positive idea of these, a negative idea of 
blue and yellow. If I had all my lifetime been subject 
to coercion, and had never performed an act of volition, 
I should have a negative idea of free agency. If I had 
never in my life found my volition opposed, I should have 
a negative idea of coercion. As it is, I have a positive 
idea of both. I desire to thrust my arm out in open space, 
and my desire is carried into effect. Here is the positive 
consciousness of freedom. I try to thrust it through a 
wall, and am resisted. Here is the positive consciousness 



1 Essay, b. iii. ch. 4, § 11. 

2 By simple ideas are meant the immediate objects of sensation or reflec- 
tion in Locke's sense of the terms, such as color and sound, which can be 
apprehended only by actual sight or hearing; perception and volition, 
which can be known only by the actual experience of self-consciousness. 
Complex notions may be formed from these by an act of pure imagina- 
tion, but the elements must be given beforehand. Compare Locke, I. c. 



PROLEGOMENA LOGICA; 51 

of coercion. 1 "When Locke declared infinite space and 
infinite duration to be negative ideas, he was right, if 
we grant his hypothesis of their origin. The former he 
derived from sensation ; and all the space which we can 
actually perceive by the senses is finite : the latter he 
derived from reflection; and every duration which we 
have personally experienced is finite also. Those who do 
not accede to his conclusion ground their dissent on a 
denial of his premises. 3 The language in which the con- 
cept is expressed is in this respect altogether indifferent. 
We may speak of the same act as voluntary, or not con- 
strained, as compulsory, or not voluntary. The test of 
its positive or negative character is to be found in the 
question, Has it ever been realized in an intuitive pre- 
sentation ? 

Those ideas whose negative character depends merely 
on the deficiences of individual experience, and which 
may therefore be described as accidentally or relatively 
negative^ are beyond the consideration of pure Logic, or 



1 Some philosophers represent the idea of freedom as a negative one. 
Thus Kant (Bechtslehre, p. 28, ed. Schubert) and Fichte (Kritik aller Offen- 
barung, § 2) describe it as merely an absence of the feeling of compulsion. 
This description would be correct, if we had never performed an act in 
our lives except under coercion. As it is, the idea of freedom is as posi- 
tive as that of restraint, both being at different times presented in actual 
consciousness. The same is the case with heat and cold, good and evil, 
and other pairs of contraries, each of which, as a phenomenon of con- 
sciousness, is as positive as the other. What may be their respective rela- 
tions to a transcendental cause beyond the sphere of consciousness, we 
have no means of determining. 

2 See Cousin, Histoire de la PMlosophie, lecon xviii. On the other hand, 
Locke's conclusion is supported, though on different grounds, by Sir W. 
Hamilton, Discussions, p. 605, who shows that an absolute^ first unit of 
Space or Time, and an infinite extent of either, are both equally inconceiv- 
able. 



52 PROLEGOMENA LOGICA. 

pure Metaphysics, which deal only with those conditions 
of thought which are common to all mankind. Hence the 
only negative ideas with which the logician or metaphysi- 
cian as such is concerned, are those which arise from an 
attempt to transcend the conditions of all human thought. 
If the human mind is subject to laws and limitations 
which it is unable to transgress by any effort of thought 
(and that this is the case will be shown at a further stage 
of our inquiry), there will arise in relation to these a class 
of notions which may be distinguished as essentially or 
absolutely negative. Such negative notions, however, must 
not be confounded with the absence of all mental activity. 
They imply at once an attempt to think, and a failure in 
that attempt. 1 The language by which such notions are 
indicated is not like a word in an unknown tongue, which 
excites no corresponding affection in the mind of the 
hearer: it indicates a relation, if only of difference, to 
that of which we are positively conscious, and a conse- 
quent effort to pass from one to the other. Thus, if it be 
true that the infinite is not a positive object of human 
thought, it will not follow that the word is to us wholly 
unmeaning. We may attempt to separate the condition 
of finiteness from our conception of a given object, though 
the result may ultimately involve a self-contradiction. We 
may attempt in like manner to conceive a space enclosed 
by two straight lines, and it is not till after the attempt 
has been, made that we become aware that the expression 
bilinear figure admits of no corresponding notion. And it 
may frequently happen, owing to the use of language as a 
substitute for positive thought, that a process of reasoning 
may be carried on to a considerable length, without the 
reasoner being aware of the essentially inconceivable 

1 See Sir W. Hamilton's Discussions, p. G02. 



PROLEGOMENA LOGICA. 53 

character of the terms which he is employing. If we 
assume without inquiry the possible existence of a circular 
square, we may demonstrate of it in succession all the 
properties of the circle and all those of the square, without 
at the moment perceiving their incompatibility with each 
other. Such a self-deception is still easier when the nega- 
tive character depends, not on the union of attributes 
which cannot be conceived in conjunction, but on the 
separation of those which cannot be conceived apart. We 
may easily analyze in language that which it is impossible 
to analyze in thought. Thus we can neither perceive nor 
imagine color without extension ; an unextended color is 
therefore a purely negative notion. Yet many philoso- 
phers of eminence have maintained that the connection 
between these two ideas is merely one of association, and 
have reasoned concerning color apart from extension with 
as much confidence as if their language represented a 
positive thought. The speculations concerning the seat 
of the soul may be cited as another instance of the same 
kind. Position in space and occupation of space are cor- 
relative notions; neither is conceivable apart from the 
other. Yet the above speculations for the most part 
proceed on the tacit assumption that it is possible to 
assign a local habitation to an unextended substance. 
Such is the influence of language, even when representing, 
not thought, but its negation. 

If thought is operative only within the field of possible 
experience, it follows, that we are not entitled, in any act 
of thought, to add to the data given in the concept, withr 
out a fresh appeal to intuition. I have in my mind the 
notion of a centaur, as a creature with the upper parts of 
a man and the lower parts of a horse. But this concept 
does not in itself contain the attribute of existence in space 

5# 



54 PROLEGOMENA LOGICA. 

as an object of possible perception. I am therefore not 
warranted in thinking of the centaur as so existing, until 
the attribute is supplied from its proper source of presenta- 
tion, which in this case is sensible experience. If my 
notion of man does not contain the attribute of mortality, 
I may think of man as mortal or as immortal, but I can- 
not determine which of these judgments is true, i. e., is in 
accordance with the corresponding intuition, without com- 
paring them with the fact as presented by experience. In 
the mere notion of two straight lines, it is not contained 
that they cannot inclose a space ; and in the mere notions 
of the numbers 7 and 5, it is not contained that their sum 
is 12. Neither of these judgments, therefore, can be deter- 
mined to be true without an appeal to some fact or other 
of intuition. This limitation of the province of thought 
implies some important consequences, which will appear 
when we come to consider the character of the laws of 
pure thinking recognized by Logic. 

Before taking leave of this part of our subject, it may be 
useful to point out one or two questions of controversy, 
to which the distinction between Thought and other facts 
of consciousness may be applied with advantage. 

It has been remarked by Sir William Hamilton, 1 that 
the whole controversy of Nominalism and Conceptualism 
is founded on the ambiguity of the terms employed ; on 
the want, that is, of an accurate distinction, such as is fur- 
nished by the German Anschauung and Begriff, between 
the individual intuitions of sense and imagination, and 
the general concepts of the understanding. We may ob- 
serve further, that the controversy between Nominalism 
and Realism may be, if not absolutely decided, at least 
considerably simplified, by attending to the same distinc- 

1 Beid's Works, p. 412. 



PROLEGOMENA LOGICA. 55 

tion. Some recent critics, in examining this question, have 
managed to introduce additional confusion into what was 
sufficiently confused before. It is asked, for example, 
whether the great division of animal, vegetable, and min- 
eral is not to be regarded as the work of nature, rather 
than as the arbitrary product of man's classification. Un- 
doubtedly : but what has that to do with the question of 
the existence of Universals out of the mind ? We admit, 
that is, that nature has stamped on certain locally distinct 
individuals a number of prominent features of resem- 
blance, which cannot fail to strike the eye of an observer. 
But has she thereby produced anything more than one 
set of attributes existing in one individual in one place, 
and another similar set existing in another individual in 
another place ? But when, by an act of mind, we have 
abstracted from the existence in space under which 
all objects of sense are presented, and, by virtue of that 
abstraction, have advanced from individual similarity to 
specific unity, from the similar attributes of several objects 
to the mutual relation of all, the results of the process can 
only be regarded as the offspring of our minds. This con- 
sideration does not indeed prove decisively the impossi- 
bility of universals a parte rei, but it shows that no argu- 
ment in favor of their existence can be drawn from the 
observed uniformities of nature. 1 

Another subject of dispute between different schools of 
philosophy is, What are the limits of definition ? The 
Scholastic Logicians, holding that definition was by genus 
and differentia, very consistently laid it down as a canon, 



1 Since the publication of the first edition^ of this work, I have been 
gratified at finding the same view maintained in an able discussion by 
M. de Remusat, Abelard, vol. ii. p. 125. 



5Q PROLEGOMENA LOGICA. 

that no object was definable which could not be regarded 
as a Species. Summa genera and individuals were by 
this rule incapable of definition. On the other hand, Des- 
cartes and Locke, rejecting this restriction, maintain that 
simple ideas alone cannot be defined. Both are right, ac- 
cording to their different meanings of definition. With 
the former, it signifies the resolution of a complex general 
concept into the simpler concepts which it comprehends. 
With the latter, it is the resolution of a complex individ- 
ual object of sense into the simpler objects of which it is 
composed. The one is a mental analysis of notions, the 
other a sensible analysis of intuitions. ~No definition, as 
Locke truly observes, will convey the idea of whiteness to 
a blind man ; i. e., it will not enable him to form a sensible 
image of the color. But no definition (in the scholastic 
sense) was ever intended to accomplish this object. The 
far-famed animal rationale does not do it for man ; and 
for the very sufficient reason, that concepts, as such, are 
not capable of being presented in sense or imagination. 
If the purpose of logical definition were to enable us to 
form an idea, i. e., a representative image of an object, 
pointing it out with the finger would be a far more satis- 
factory definition than any verbal analysis. 1 But ideas, in 
this sense, have no connection with logical definition. 
Locke's ideas of sensation, simple or complex, are all ex- 
cluded from the province of definition, as being individu- 
als, i. e., as not being concepts at all. On the other hand, 
the concept whiteness, as a species of color, is capable of 
definition by its optical differentia, as a color produced by 
equal mixture of the simple rays. An example adduced 



1 Arist. Anal. Post. II. 7. oh yap 8?) 8el£ei ye ttj cuo&^rcf tj t£ 5a/cr^A&>. 
Cf. Mill's Logic, vol. i. p. 183. 



PROLEGOMENA LOGICA. 57 

by Descartes, as well as by Locke and Leibnitz, 1 will illus- 
trate the distinction still more clearly. The concept of a 
chiliogon is a regular polygon of 1000 sides. As addressed 
to the sense, this definition would not enable any man to 
distinguish an individual figure of the kind by sight from 
another which had 999 sides ; but, as addressed to the 
understanding, it is sufficient for the demonstration of the 
mathematical properties of the figure. Yet even here, in- 
tuition, though not directly applied, is the virtual test of 
the possibility of the conception. I may not be able dis- 
tinctly to represent in an image or construct in a figure a 
thousand sides at once ; but it is from my intuitive con- 
sciousness of the same attributes as existing on a more 
limited scale, that I know that there is nothing incompati- 
ble between the number of a thousand sides and the prop- 
erty of enclosing a space. Under this conviction the sym- 
bolical takes the place of the intuitive cognition ; and we 
are enabled, by the aid of language, to think of the figure 
in certain relations, without actually constructing it with 
the hand or in the mind. 

The same distinction will furnish a ground for criticizing 
certain popular systems of logical notation. If Logic is 
exclusively concerned with Thought, and Thought is ex- 
clusively concerned with Concepts, it is impossible to ap- 
prove of a practice, sanctioned by some eminent Logicians, 
of representing the relation of terms in a syllogism by that 
of figures in a diagram. To illustrate, for example, the 
position of the terms in Barbara, by a diagram of three 
circles, one within another, is to lose sight of the distinc- 
tive mark of a concept, that it cannot be presented to the 
sense, and tends to confuse the mental inclusion of one 

1 See Descartes, Meditatio Sexta ; Locke, Essay, ii. 29, 13 ; Leibnitz, Nou- 
veaux Essais, ii. 29, 13. 



58 PROLEGOMENA LOGICA. 

notion in the sphere of another, with the local inclusion of 
a smaller portion of space in a larger. 1 The diagrams of 
Geometry in this respect furnish no precedent ; for they do 
not illustrate the form of the thought, but the matter, not 
the general character of the demonstration as a reasoning 
process, but its special application as a reasoning about 
magnitudes in space. Still less is such a practice justified 
by the test of conceivability which has been mentioned 
above, the possibility, namely, of individualizing the attri- 
butes comprehended in a concept. For, whereas that test 
is employed to determine the conceivability of the actual 
contents of each separate concept, the logical diagrams are 
designed to represent the universal relations in which all 
concepts, whatever be their several contents, formally stand 
towards each other. The contrast between these two, as 
legitimate and illegitimate appeals to intuition, will more 
fully appear in the sequel. 

1 " Da der Mensch die Sprache hat," says Hegel, "als das der Vernunft 
eigenthiimliche Bezeichnungsmittel, so ist es em miissiger Einfall, sieh 
nach einer unvollkommnern Darstellungsweise umsehen und damit qualen 
zu wollen. Der Begriff kann als soldier wesentlich nur rait dem Geiste 
aufgefasst werden. Es ist vergeblicli, inn durch Raumfiguren und alge- 
braische Zeichen zum Behufe des aiissertichen Aages und einer begrifflo- 
sen, mechanischen Behandlungsweise, eines Calculs, festhalten zu wollen." 
"While dissenting totally from the Hegelian view of Logic, I cannot resist 
quoting the above passage, as applicable to every view of the Science 
which recognizes the essential distinction between thought and intuition. 



CHAPTER II. 

ON THE THREE OPERATIONS OF THOUGHT. 

Concerning the threefold division of the mental opera- 
tions usually acknowledged by Logicians, it has been 
questioned whether they are properly to be regarded as 
distinct acts of Thought or not. The question may be 
considerably simplified, by discriminating between different 
principles of identity or distinctness, as applicable severally 
to mental and material objects. The only natural and 
necessary principle of distinction between objects is the 
numerical diversity of individuals. In this respect, not 
only the several acts of Simple Apprehension, Judgment, 
and Reasoning, but every single act of each class, is dis- 
tinct from every other. An act of reasoning which I 
perform to-day is numerically distinct from any act per- 
formed yesterday, though both may be governed by the 
same laws and applied to the same objects. Beyond this, 
any principle of specific identity or diversity is to a certain 
extent arbitrary and artificial. The only ground of dis- 
tinction between a natural and an unnatural classification 
of individuals depends upon the frequency with which 
we have occasion to view them in this or that relation ; in 
other words, on the respective utility of different points 
of view for certain given purposes. On this ground, 
Apprehension, Judgment, and Reasoning are rightly and 
necessarily regarded as distinct classes of mental opera- 
tions, relatively to Logic, inasmuch as their several pro- 



60 PROLEGOMENA LOGICA. 

ducts, the Concept, the Judgment, and the Syllogism, ex- 
hibit distinct logical forms, and require a distinct logical 
treatment. 

Psychologically, the question must be examined on 
somewhat different grounds. It may be urged, for exam- 
ple, on the one side, that the several operations are the 
product of the simple faculty of Comparison ; that they 
are not in act ever separable from each other, Apprehension 
being always accompanied by Judgment, and Judgment 
by Apprehension, and Reasoning by both; that the mind, 
one and indivisible, is wholly employed in each. On the 
other side, it may be answered, that acts of Comparison 
may be regarded as specifically distinct, as engaged on 
distinct objects ; that the comparison of attributes with 
each other, of concepts, immediately in themselves, or 
mediately with a common third concept, are pro tanto 
distinct acts; that the same mind is not always equally 
skilful in all three; and other arguments of the like kind. 
Both these opposite opinions may be accepted as true, if 
we attend to the different points of view which render the 
decision of all such matters of controversy in some degree 
arbitrary. 

The distinction between the faculties and parts of the 
mind is based on a principle exactly the reverse of that 
by which a similar distinction is made relatively to the 
body. The members of the latter are given as logically 
and numerically distinct, and thus furnish a preexisting 
basis for the classification of their several operations. 
Thus, seeing and hearing are distinguished from each 
other, as the operations of the eye and the ear respec- 
tively ; and the use of the pen, the brush, and the chisel, 
may in this point of view be classified together, as opera- 
tions of the hand; whereas, in the mind, the distinctness 



PROLEGOMENA LOGICA. 61 

of the operations is itself the ground on which, for mere 
convenience of discussion, we classify and distinguish 
different parts and faculties, as belonging to the mind 
itself. 1 The acts, therefore, must, on independent grounds, 
be determined to be identical or distinct, before we unite 
or separate them, as related to the same or diverse mental 
powers. 

Hence it appears that the classification of operations, 
relatively to distinct mental faculties, is contingent upon 
the adoption of some independent principle for classifying 
the same operations in themselves. In the present state 
of Psychology, much must be left to the discretion of 
individual inquirers ; no one division having been so 
universally adopted by philosophers, or having led to such 
important results, as to render imperative its adoption as 
the division kolt e^o^v of psychologers. But to suppose a 
distinct mental faculty for each of the three logical opera- 
tions, solely on the ground of the distinct objects compared 
in each, is, to say the least, to make Psychology unneces- 
sarily complicated, and to offend against a rule of great 
weight in all systems of classification, Entia non sunt 
maUiplicanda prceter necessitatem. Indeed, the several 
phenomena of conception, judgment, and reasoning, 
viewed merely as mental acts, and without reference to 
the diversity of the data from which the act commences 
and with which it deals, appear to furnish far more promi- 



1 " Nous ne savons que l'ame humaine possede certaines facultes, que 
parce que nous voyons en elle certains phenomenes se produire. Ainsi, 
parce que nous observons qu'elle sent, qu'elle pense, qu'elle se souvient, 
nous en eoneluons qu'elle a la capacite de sentir, la capacite de penser, la 
capacite de se souvenir; et ce sont ces capacites que nous appclons ses fac- 
ulte's." — Jouffroy, Des facultes de fame humaine, {Melanges PMIosophiques, 
p. 313, 2d ed.) 

6 



62 PROLEGOMENA LOGIC A. 

nent features of similarity than of difference. They are 
effected by the same means; they are governed by the 
same laws ; they are confined within the same limits ; 
they admit of the same distinctions of material and formal 
validity. The psychological analysis of any one may be 
applied, almost in the same words, to the others ; and so 
far as thought alone is concerned (though not always in 
the possession and management of the materials upon 
which thought is exercised), the same mental qualities 
are manifested in the right performance of each. In a 
psychological point of view, to enumerate separate mental 
faculties, as giving rise to the various products of thought, 
is, to say the least, to encumber the science with unneces- 
sary and perplexing distinctions. It will be sufficient to 
refer them to the single faculty of Thought, the operation 
of which is in all cases Comparison. 1 

But the faculty of Thought, though uniform in its own 
nature and in the manner of its operation, may yet give 
rise to different products, according to the diversity of the 
materials upon which it operates ; and this difference, as 
has already been observed, forms the basis of the classifi- 
cation usually adopted in Logic. Hence, from the different 
points of view in which thought is contemplated by the 
two sciences, there arises some diversity of detail, which it 
is desirable to point out more particularly. 

Extending the terms Apprehension and Judgment be- 
yond the region of Thought proper, 2 it may be laid clown, 



1 See Sir W. Hamilton's Lectures on Metaphysics, Lect. xxxiv. 

2 The division into Simple Apprehension, Judgment, and Reasoning, is 
usually given as one of the discursive faculties. Yet even Logicians have 
extended it to the powers of perception and imagination. Indeed, these 
several faculties have shared in the confusion arising from the vague use, 
in modern philosophy, of the term idea. A striking instance is afforded 



PROLEGOMENA LOGICA. bd 

as a general canon of Psychology, that the unit of con- 
sciousness is a judgment ; in other words, that every act of 
consciousness, intuitive or discursive, is comprised in a 
conviction of the presence of its object, either internally 
in the mind or externally in space. The result of every 
such act must thus be generally stated in the proposition, 
" This is here." Consequently, at least with reference to 
the primary and spontaneous, as distinguished from the 
secondary and reflex acts of consciousness, it is more cor- 
rect to describe Aj^prehension as the analysis of Judgments, 
than Judgment as the synthesis of Apprehensions. 1 

In a psychological point of view, therefore, it is incor- 
rect to describe Simple Apprehension as the first operation 
of the mind. In one sense, indeed, the relation of prior 
and posterior is altogether out of place : Chronologically, 
inasmuch as every Apprehension is simultaneous with a 
Judgment, and every Judgment with an Apprehension ; 
and logically, inasmuch as Judgment cannot exist without 
Apprehension, nor Apprehension without Judgment. In 
another sense, however, we may properly say that Judg- 
ment is prior to Apprehension ; meaning that the subject 
and the object are first given in their mutual relation to 
each other, before either of them can itself become a sep- 
arate object of attention. But when a corresponding 
division is adopted of the operations of Thought, properly 
so called, the same order of priority cannot be observed. 
Every operation of thought is a judgment, in the psycho- 
logical sense of the term ; but the psychological judgment 
must not be confounded with the logical. The former is 

by Wolf, in his account of Apprehension and Judgment. Phil. Mat., 
§$ 33—39. 

1 See Reid, Intellectual Powers, Essay iv. ch. 3, with Sir W, Hamilton's 
Commentary. 



64 PROLEGOMENA LOGICA. 

the judgment of a relation between the conscious subject 
and the immediate object of consciousness ; the latter is 
the judgment of a relation which two objects of thought 
bear to each other. The former cannot be distinguished 
as true or false, inasmuch as the object is thereby only 
judged to be present at the moment when we are con- 
scious of it as affecting us in a certain manner ; and this 
consciousness is necessarily true. The latter is true or 
false according as the relations thought as existing be- 
tween certain concepts are actually found in the objects 
represented by those concepts or not. The logical judg- 
ment necessarily contains two concepts, and hence must be 
regarded as logically and chronologically posterior to the 
conception, which requires one only. The psychological 
judgment is coeval with the first act of consciousness, and 
is implied in every mental process, w r hether of intuition or 
of thought. It cannot, therefore, be called prior or poste- 
rior to any other mental operation, for there is no mental 
operation in which it does not take place ; but the judg- 
ments of intuition are logically and chronologically prior 
to the judgments of thought. 1 Conception is a psychologi- 

1 Of the important distinction between chronological and logical priority 
(the tempore and natura of the scholastic post-predicaments), it will he 
sufficient to quote one ancient and one modern exposition. Aristotle (for 
name and thing), Categ. ch. 12: Uporepov erepov zTtpov Xeyerat reTpax&s, 
ivpiaTov /xeu Kal Kvpioorara Kara xpo^ov, Ka& b Trpeo-fivT€pov krepov eiepov Kal 
irahcuorepov \eyerai. . . . Aevrepov Se to (j.$) o.vt i<jt pi<pov Kara ttju tov dvai 
a.Ko\ov&r)0-iv, diov to %v tSov 5vo irpoTepow SuotV fj.lv yap ovtoov aKoXov&e? 
evd-bs to lit elvai, iuhs 8e ovtos ovk avayKalov dvo elvai. Bletaph. viii. 8. 2. 
Fiacres 5/? T7js TOiavTTjS TrpoTtpa iarlv 7) ivipyeia Kal \6yca Kal Trj ov(r{a' 
Xp6vq> 8' Zctti /xeu &s, eari 8' a>s ov. Cousin, Programme d'un cours de 
Plulosophie: "Une connaissance est anterieure a une autre dans 1'ordre 
logique, en tant qu'elle l'autorise; elle est alors son antecedent logique. 
Une connaissance est anterieure a une autre dans 1'ordre psychologique, 
en tant qu'elle se produit avant elle dans l'csprit humain; elle est alors son 



PROLEGOMENA LOGICA. 65 

cal judgment, but not a logical one, and is properly ranked 
as the first operation of Thought, inasmuch as it is the 
simplest. 

As the design of the present essay is not to consider 
Psychology in itself, but Psychology in its relation to 
Logic, I shall content myself with accepting the three 
operations of Thought as they are commonly distinguished 
by Logicians, examining them with a view of ascertaining 
what light Psychology can throw on the province and laws 
of each. Other points of view, and other principles* of 
classification, need not be further discussed in this place. 
In relation to their several logical products, the three 
operations may be distinguished as follows. 

Conceiving has been already explained as the individu- 
alizing of certain attributes comprehended in a general 
notion and expressed in a general term; the representation, 
namely, of such attributes as coexisting in a possible ob- 
ject of intuition. Language, as before observed, is, in its 
earliest operations, a sign, not of concepts, but of intu- 
itions. Its earliest terms are employed as the proper 
names of individual objects. Conception does not take 
place till after we have learned to give the same name to 
various individuals presented to us with certain differences 
of attributes, and hence to associate it with a portion 
only, not with the whole, of what is presented in each. 
This may be distinguished as Abstraction, a spontaneous, 
though not always a voluntary act, the concentration of 
the mind on certain portions only of a given object in 
relation to its name. This must not be treated, as is 
frequently done by Logicians, as a conscious process of 

antecedent psychologique." For some admirable applications of the above 
distinction, see the same author's criticism of Locke, Cours de Philosophie, 
lecon 17. 

6* 



66 PROLEGOMENA LOGICA. 

thought, being only a preliminary condition to thinking, 
taking place in the majority of cases unconsciously, dur- 
ing the gradual acquisition of speech. 1 Our names thus 
gradually acquire a signification, being transformed from 
proper names to appellatives. Finally, the act of concep- 
tion consists in contemplating the attributes thus com- 
bined in the signification of a name as coexisting, along 
with individual features, in a possible object of intuition, 
and hence, apart from the individual features, as indif- 
ferently representing all such objects. This representative 
collection of attributes, combined by means of a sign, is a 
Concept. 

In the above remarks, the office of language is con- 
sidered as it now exists and is taught, not as it might pos- 
sibly have been originally created. "We do not form our 
own language, but receive it ready formed ; and its teach- 
ing, whether true or deceitful, whether promoting or dis- 
torting the right development of the mind, does, as 
matter of fact, impress us from our infancy upwards with 
certain associations, and casts our earliest thoughts in a 
certain mould, from which no future effort can wholly 
emancipate us. I am not now considering what might 
have been the course of our mental growth had we been 
the original inventors of our mother tongue, or if we had 
been born among a people with whom (as in a hypothesis 

1 Abstraction, as described by Stewart, Elements, vol. i. ch. 4, answers in 
essential points to what I hare here described. It should be observed, 
however, that by language as it now operates, whatever may have been 
the case in its first formation, the question as to what attributes shall be 
abstracted and what retained, is in a great measure determined for us. 
The process must thus be distinguished from the voluntary abstraction im- 
plied in all operations of thought. On Abstraction, as distinguished from 
Attention, see Tissot, Anthropologic, vol. i. p. 142. 



PROLEGOMENA LOGICA. 67 

of Reid's 1 ) every sound represented a complete sentence. 
Language is not here considered as it might have been in- 
vented by a conclave of imaginary philosophers, or as it 
may have influenced the thoughts of Adam in Paradise; 
but as it does influence the thoughts of children born into 
the world, the offspring of articulately-speaking parents. 

As in Conception a single general notion is considered 
in its relation to a possible object of intuition, so in Judg- 
ment two such notions are considered as related to a com- 
mon object. When I assert that A is B, I do not mean 
that the attributes constituting the concept A are identical 
with those constituting the concept B, — for this is only 
true in identical judgments, — but that the object in which 
the one set of attributes is found is the same as that in 
which the other set is found. To assert that all philoso- 
phers are liable to error, is not to assert that the significa- 
tion of the term philosopher is identical with that of liable 
to error; but that the attributes comprehended in these 
two distinct terms are in some manner united in the same 
subject. To ask what constitutes unity or identity in a 
subject of attributes, is to enter on a deep metaphysical 
question, the discussion of which must be postponed to a 
later stage of our inquiry; it is sufficient for the present 
to observe, that the common language and common 
thought of mankind universally acknowledge something 
of the kind, assuming, whether they can explain it or not, 
that a certain smell and color and form, which are distinct 
attributes, are in some way related, as parts or qualities, 
to some one thing which we call a rose ; and that, when I 
assert that the rose is fragrant, I imply that the thing 



1 Correspondence, Letter xi. to Dr. James Gregory. See p. 71 of Sir W. 
Hamilton's edition. 



68 PROLEGOMENA LOGICA. 

which affects in a certain way my power of sight is in 
some manner identical with that which affects in a cer- 
tain way my power of smell. The metaphysical problem 
thus lies at the bottom both of Conception and of Judg- 
ment, and, whether it admits of satisfactory explanation 
or not, must be included as a fact in any description of the 
several operation's of Thought. 

Reasoning is the most complex of the three operations, 
as in it two concepts are determined to be in a certain 
manner related to each other, through the medium of their 
mutual relations to a third concept. This operation is 
therefore treated last in order. 1 The several relations 
asserted in the premises and deduced in the conclusion, 
are of the same nature as those implied in Judgment, and 
lead to the same metaphysical difficulties. These, together 
with the logical and psychological character of the Laws 
of Thought, will be considered in a future chapter. For 
the present it will be sufficient to attempt, in accord- 
ance with the above observations, a definition of the 
products of the several acts of Thought, the Concept, 
the Judgment, and the Syllogism, the legitimate objects 
of Formal Logic. 

A Concej3t is a collection of attributes, united by a sign, 
and representing a possible object of intuition. 

A Judgment is a combination of two concepts, related 
to one or more common objects of possible intuition. 



1 " Judicium notiones conjungit vel separat, adeoque eas supponit. 
Ratiocinando ex notionibus et judiciis prseviis elicitur judicium ulterius, 
adeoque ratiocinatio notiones et judicia supponit. Ergo notio est operatio 
prima, judicium secunda, discursus tertia." — Wolf, Phil. Rat. § 53. But 
Wolf, as before observed, has not accurately distinguished between the 
perceptive and discursive faculties. Hi* remark is true, though only in a 
much narrower sense than that in which he designed it. 



PROLEGOMENA LOGICA. 69 

A Syllogism is a combination of two judgments, neces- 
sitating a third judgment as the consequence of their 
mutual relation. 

The definition above given of a Judgment renders ne- 
cessary a few remarks on a class of propositions, whose 
true logical character has been considerably misappre- 
hended by eminent authorities. According to the above 
definition, every judgment in Logic must be regarded as a 
combination of concepts; every term of such judgment, 
as the sign of a concept. This is no less true of singular 
than of common judgments, and the neglect of it has 
given rise to some errors in the logical treatment of prop- 
ositions. "Proper names," says Mr. Mill, "denote the 
individuals who are called by them ; but they do not indi- 
cate or imply any attributes as belonging to those indi- 
viduals. When we name a child by the name Mary, or 
a dog by the name Ca3sar, these names are simply marks 
used to enable those individuals to be made subjects of 
discourse. It may be said, indeed, that we must have had 
some reason for giving them those names rather than any 
others ; and this is true : but the name, once given, be- 
comes independent of the reason. A man may have been 
named John, because that was the name of his father ; a 
town may have been named Dartmouth, because it is situ- 
ated at the mouth of the Dart. But it is no part of the 
signification of the word John, that the father of the per- 
son so called bore the same name ; nor even of the word 
Dartmouth, to be situated at the mouth of the Dart." 1 

These remarks are true so far as the name alone is con- 
cerned, or as regards the reason of its being imposed, at a 
certain time, on a certain man. But, then, the man, as an 
individual existing at some past time, cannot become im- 

1 Mill's Logic, vol. i. p. 40. 



70 PROLEGOMENA LOGICA. 

mediately an object of thought, and hence is not, properly- 
speaking, the subject of any logical proposition. If I say, 
" Caesar was the conqueror of Pompey," the immediate 
object of my thought is not Caesar as an individual exist- 
ing nearly two thousand years ago, but a concept now 
present in my mind, comprising certain attributes, which I 
believe to have coexisted in a certain man. I may histori- 
cally know that these attributes existed in one individual 
only ; and hence my concept, virtually universal, is actually 
singular, from the accident of its being predicable of that 
individual only. But there is no logical objection to the 
theory that the whole history of mankind maybe repeated 
at recurring intervals, and that the name and actions of 
Caesar may be successively found in various individuals at 
corresponding periods of every cycle. 

" Alter erit turn Tiphys, et altera quae vehat Argo 
Delectos heroas: erunt etiam altera bella; 
Atque iterum ad Trojam magnus mittetur Achilles." 

These remarks will suggest a correction of the ordinary 
logical account of the quantity of propositions, which 
should have been made long ago. The subjects of all 
logical judgments are concepts : the true singular proposi- 
tion in Logic is not one in which the concept is materially 
limited to an individual by extralogical considerations, but 
one in which it is formally so limited by a sign of indi- 
viduality. In scholastic language, only individua demon- 
strative and not, as is vulgarly taught, individua signata, 
are properly the subjects of singular propositions. 1 In- 
definite, or, as they should rather be called, indesignate 2 

1 Cf. Fries, System der Logik, § 22. His principle is sound, though some 
of his instances are inaccurate. 

2 Properly speaking, particular propositions are indefinite, singulars and 



PROLEGOMENA LOGICA. 71 

propositions, are an anomaly in Logic, no less when the 
subject is a singular than when it is a common term. In 
both, the quantity can only be known by the matter, and, 
in both, an appeal to the matter is extralogical. 

The same considerations will also show the propriety 
of Aristotle's limitation of the logical verb to the present 
tense only. All thought is a consciousness of present 
mental acts, and its object is not the past event, but the 
present concept of it. Hence the office of the verb in 
Logic is not to declare the past or future connection of an 
attribute with its subject in the represented fact, but to 
declare the present coexistence of two concepts in the 
representative act of thought. 1 

Before quitting this portion of the subject it will be 
desirable to compare the conclusions arrived at with those 
of two eminent philosophers, from both of whom they 
appear, verbally at least, to differ in a slight degree. 

Locke's well-known definition of knowledge, " The per- 
ception of the agreement or disagreement of two ideas," 
has been somewhat severely commented on by his illus- 
trious critic, M. Cousin. 2 The French philosopher shows 
clearly that, in many of our judgments, we cannot be said 



universals definite. For when I say Some. A is B, I leave it altogether 
undetermined how many, and whether any given A is included or not. 
For this reason it is better to adopt the term indesignate, suggested by Sir 
W. Hamilton. 

1 " Copula non est nisi verbum substantivum prsesentis temporis. De- 
notat enim nexum inter subjectum et proedicatum intercedentem, qualis 
nempe repra;sentatur in ideis nostris. Cum igitur in omni judicio nexus 
ille semper sit aliquid praasens, copula non esse potest nisi verbum sub- 
stantivum pi-Eesentis temporis." —Wolf, Phil Bat. § 202. 

2 Cours de Philosophie, lecon 23. Compare Jouffroy's Eeid, Preface, pp. 
130, 133, sqq. For other criticisms, see Reid, Intellectual Powers, Essay I. 
ch. 7; Essay VI. ch. 3; Leibnitz, Nouveaux Essais, IV. 1. 



72 PROLEGOMENA LOGICA. 

to have distinct notions of terms united, prior to pro- 
nouncing on the fact of their agreement. The distinc- 
tions drawn in the preceding remarks will, I think, furnish 
a ground for a more exact decision of the point at issue 
than has been given either by the English philosopher or 
his French censor. Locke's definition abounds in verbal 
inaccuracy, for which, however, the author is not entirely 
responsible, as it is partly owing to the unsettled significa- 
tion, in his day, of philosophical terms, which have since 
been more accurately determined. Taking Perception in 
the strict sense to which it has been determined by Reid 
and his successors, it is not correct to say, in general 
terms, that the agreement of ideas is in all cases perceived. 
Extending Knowledge, as Locke himself does, to include 
the evidence of the senses, 1 it is incorrect to say that, in 
all knowledge, we have a distinct consciousness of two 
ideas and their agreement. And the term Idea itself, 
used loosely by Locke, as by Descartes, for any object 
of consciousness, admits of a variety of subordinate senses, 
in some of which the definition is assuredly inaccurate. 
But, as limited to the logical judgment proper, as it has 
been above distinguished from the psychological, the defi- 
nition is substantially correct, though susceptible of some 
verbal improvement. In every logical judgment there is 
a union of concepts ; and every concept is represented by 
a sign. The concepts themselves must be regarded as ex- 
isting in the mind before their union ; and, the signs being 
practically furnished by the existing terms of a language, 
the logical judgment maybe properly described as formed 
by the combination of concepts; as its representative, the 
proposition, is formed by the combination of terms. But 
to the judgments distinguished as psychological the defi- 

i Essmj,B. IV. ch.2. $ 14. 



PROLEGOMENA LOGICA. 73 

nition of Locke is inapplicable; and here the objections of 
M. Cousin may be urged with full effect. Such are all the 
spontaneous judgments of the perceptive and imaginative 
faculties. Such, too, is the Cartesian cogito, ergo sum, a 
primitive judgment, not of the senses, but of the internal 
consciousness, which the opponents of Descartes, from 
Gassendi to Kant, have misrepresented as a logical reason- 
ing from concepts. 1 The definition of Locke is therefore 
correct, as far as regards judgments of thought, properly 
so called ; judgments formed by means of concepts, and, 
consequently, of language, and whose constituent parts 
are given piecemeal in words, and put together by the 
mind in the act of judging. It is incorrect, as regards all 
judgments, whether concerning the ego or the non-ego, 
which the mind forms for itself, by an immediate act of 
consciousness, without the aid of verbal or other signs of 
voluntary intuition. 

From the definition of Locke we proceed to consider 
that of Kant. In the Critical Philosophy, Thought and 
Judgment are synonymous, and the act of the understand- 
ing. The understanding may be defined indifferently, the 
faculty of thinking, or the faculty of judging ; for all 
thought is cognition by means of concepts ; and all con- 
cepts are the predicates of possible judgments, and are, by 
such judgments, referred to objects of sensible intuition, 
either immediately, or through the interposition of lower 

1 See an article in Cousin's Fragments PMlosophiques, " Sur le vrai sens 
du cogito, ergo sum." To tins I am indebted for the following quotation 
from Descartes himself: " Cum itaque quis advertit se cogitare, atque hide 
sequi se existere, quamvis forte nunquam antea qucesiverit quid sit cogi- 
tatio nee quid existcntia, non potest tamen non utramque satis nosse, ut 
sibi in hac parte satisfaciat." — Hesponsio ad sexlas objediones. See also 
Clauberg, Logica, Qu. clx. 

7 



74 PROLEGOMENA LOGICA. 

concepts. 1 The intuitions of sense being, according to 
Kant's theory of perception, immediate representations of 
objects, the judgment is thus the mediate cognition of an 
object, or the representation of a representation. 2 

In a psychological point of view, the Kantian definition 
of Judgment is too narrow ; as it virtually denies that any 
act of Judgment whatever is performed in the exercise of 
the intuitive fuculties ; a denial which the author repeats 
still more explicitly in other passages. 3 In a logical point 
of view, it is too wide ; the province of Judgment being 
made coextensive with the whole of Thought, including, 
therefore, under it, Conception or Simple Apprehension. 
EA T ery concept, according to Kant, is the predicate of a 
possible judgment, in which it may be affirmed of any of 
the objects of intuition included within its sphere. He 
might have gone further, and said that, in all positive 
thinking, the possible judgment becomes an actual one. 
But it is a psychological, not a logical judgment. It 

1 " Wir konnen alle Handlungen des Verstandes auf Urtheile zuruck- 
fiihren, so dass der Verstand iiberhaupt als ein Vermogen zu urtheilen 
vorgestellt werden kann. Denn er ist nach dem Obigen ein Yermogen 
zu denken. Denken ist das Erkenntniss durch Begriffe. Begriffe aber 
beziehen sich, als Predicate moglicher Urtheile, auf irgend erne Vorstel- 
lung von einem nock unbestimmten Gegenstande." — Kritik derr.V. p. 70, 
ed. Rosenkranz. 

2 "Da kerne Vorstellung unmittelbar auf den Gegenstand geht, als bios 
die Anschauung, so wird ein Begriff niemals auf einen Gegenstand un- 
mittelbar, sondern auf irgend eine andre Vorstellung von demselben (sie 
sey Anschauung oder selbst schon Begriff) bezogen. Das Urtheil ist also 
die mittclbare Erkenntniss eines Gegenstandes, mithin die Vorstellung 
einer Vorstellung desselben." — Kritik der r. V. p. 69. 

3 " Wahrheit oder Schein sind nicht im Gegenstande, so feme er anges- 
chaut wird, sondern ira Urtheile iiber denselben, so ferae er gedacht wird. 
Man kann also zwar richtig sagen : dass die Sinne nicht irren, aber nicht 
darum, weil sie jederzeit richtig urtheilen, sondern weil sie gar nicht 
urtheilen."— Kritik der r. V. p. 238. 



PROLEGOMENA LOGICA. 75 

affirms only the mental existence of the object, as now 
present in thought; and the affirmation is necessarily true, 
whatever be the nature of the object. To make the doc- 
trine of Kant consistent, the province assigned to Judg- 
ment must be either extended or contracted. It must 
either be extended, to denote every consciousness of a 
relation between subject and object, i. e., to every opera- 
tion of mind, or it must be contracted, to denote the con- 
sciousness of a relation between two objects of thought ; 
in which case it does not extend beyond the logical judg- 
ment by means of, at least, two concepts. 

Having thus pointed out the distinction of Thought 
from other mental acts, and its various subdivisions rela- 
tively to Logic, I shall proceed to offer a few observations 
on the nature of Law, in so far as that term is applicable 
to a conscious subject. 



CHAPTER III. 

ON LAW, AS RELATED TO THOUGHT AND OTHER OBJECTS. 

The following passage from Archbishop Whately's 
Logic may serve as an appropriate introduction to this part 
of our subject. "What may be called a mathematical im- 
possibility, is that which involves an absurdity and self- 
contradiction ; e.g., that two straight lines should inclose a 
space, is not only impossible, but inconceivable, as it would 
be at variance with the definition of a straight line. And 
it should be observed, that inability to accomplish any- 
thing which is, in this sense, impossible, implies no limita- 
tion of power, and is compatible even with omnipotence, 
in the fullest sense of the word. If it be proposed, e. g., to 
construct a triangle having one of *its sides equal to the 
other two, or to find two numbers having the same ratio 
to each other as the side of a square and its diameter, it is 
not from a defect of power that we are precluded from 
solving such a problem as these ; since, in fact, the problem 
is in itself unmeaning and absurd: it is, in reality, nothing 
that is required to be done." 1 

Substantially, perhaps, this is not far from the truth. But 
it may be stated in a more satisfactory form by divesting 
it of a hypothesis which, even if true (and this w T e have no 

1 Whately's Logic, p. 353. (Sixth edition.) 



PROLEGOMENA LOGICA. 77 

means of ascertaining), may for the present purpose be 
dispensed with. 1 

When anything is said to be inconceivable, it is thereby 
acknowledged that the human mind is not altogether un- 
restricted in its operations. It is bounded not only as re- 
gards the sphere of objects of which it is permitted to take 
cognizance, but also as regards the manner in which it is 
capable of thinking about objects within that sphere. In 
other words, there are laws under which the mind is com- 
pelled to think, and which it cannot transgress, otherwise 
than negatively, by ceasing to think at all. 

The existence, then, of laws of thought is a fact of 
which our everyday consciousness assures us. Necessity, 
of Avhatsoever kind, implies a necessary agent ; that is, an 
agent acting under a law. If, then, any question can be 
proposed to the mind of man which he feels himself com- 
pelled to decide in one way only, that compulsion is at 
once an evidence of the existence of laws which, as a 
thinker, he is compelled to obey. 

And this admission is all that is required for the solution 
of such difficulties as that suggested above. If our whole 
thinking is subject to certain laws, it follows that Ave can- 
not think of any object, not even of omnipotence itself, 
except as those laws compel us. The limitation does not 
lie in the object of which we think, but in the thinking 
subject. "Whatsoever we imagine," says Hobbes, "is 
finite. Therefore there is no idea or conception of any- 
thing we call infinite. No man can have in his mind an 

1 In venturing to criticize this note, one of the most valuable portions 
of the Archbishop's work, I beg to state, that it is to the wording only of 
the first part that my remarks are intended to apply. With the just and 
philosophical distinction laid down in the same place between the three 
senses of the word impossibility, I have only to express full concurrence. 

7* 



rfO PROLEGOMENA LOGICA. 

image of infinite magnitude ; nor conceive infinite swift- 
ness, infinite time, or infinite force, or infinite power. 
When we say anything is infinite, we signify only that we 
are not able to conceive the ends and bounds of the things 
named ; having no conception of the thing, but of our own 
inability." 1 

It may be, indeed, that the conditions of possible 
thought correspond to conditions of possible being, that 
what is to us inconceivable is in itself non-existent. 2 But 
of this, from the nature of the case, it is impossible to have 
any evidence. If man, as a thinker, is subject to necessary 
laws, he cannot examine the absolute validity of the laws 
themselves, except by assuming the whole question at 
issue. For such examination must itself be conducted in 
subordination to the same conditions. Whatever weak- 
ness, therefore, there may be in the object of criticism, the 
same must necessarily affect the critical process itself. 

We may indeed believe, and ought to believe, that the 
powers which our Creator has bestowed upon us are not 
given as the instruments of deception. We may believe, 
and ought to believe, that, intellectually no less than mor- 
ally, the present life is a state of discipline and preparation 



1 Leviathan, i. 3. (p. 17, ed. Molesworth.) This opinion of Hobbes has 
been severely censured by Cud worth, Intellectual System, B. I. ch. v. § 1, 
who, however, mistakes the meaning of the assertion, both in what it ex- 
presses and in what it implies. The error of Cudworth in this respect has 
been corrected by his learned translator, Mosheim, who, though no friend 
to Hobbes's views in general, admits that in this particular his doctrine is 
not liable to the objections urged against it. See Harrison's edition of 
Cudworth, vol. ii. p. 522. 

2 In itself, distinguished from, as an object of thought. As the latter, it is 
of course impossible. The distinction between things per se and things 
as objects of thought, will be familiar to every reader of Kant. It is, in 
fact, the cardinal point of the whole Critical Philosophy. 



PROLEGOMENA LOGICA. 79 

for another ; and that the portion of knowledge which our 
limited faculties are permitted to attain to here may in- 
deed, in the eyes of a higher Intelligence, be but partial 
truth, but cannot be absolute falsehood. But, in believing 
thus, we desert the evidence of Reason to rest on that 
of Faith, and of the principles on which Reason itself 
depends it is obviously impossible to have any other 
guarantee. 

But such a faith, however well founded, has but a regu- 
lative and practical, not a speculative application. It bids 
us rest content within the limits which have been assigned 
to us : it cannot enable us to overleap them, or to exalt to 
a more absolute character the conclusions obtained by 
finite thinkers concerning finite objects of thought. 1 For 
the same condition which disqualifies us from criticizing 
the laws of thought, must also deprive us of the power of 
ascertaining how much of the results of those laws is true 
in itself, and how much is relative and dependent upon the 
particular bodily or mental constitution of man during the 
present life. To determine this question, it would be ne- 
cessary to examine the same conclusions with a new set of 
faculties, 2 and under new conditions of thought, so as to 
separate what is merely relative to the existing state of 

1 When Kant {Kritik der r. V. p. 49) declares that the objects of our in- 
tuition are not in themselves as they appear to us, he falls into the opposite 
extreme to that which he is combating: the Critic becomes a Dogmatist 
in negation. To warrant this conclusion, Ave must previously have com- 
pared things as they are with things as they seem ; a comparison which 
is, ex liypothesi, impossible. We can only say that we have no means of 
determining whether they agree or not. And, in the absence of proof 
on either side, the presumption is in favor of what is at least subjectively 
true. The onus probandi lies with the assailant, not with the defender, of 
our faculties. Cf. Royer-Collard, Jouffroy's Reicl, vol. iv. p. 412. 

2 See Reid, Intell. Powers, Essay vi. ch. 5. (p. 417, ed. Hamilton.) 



80 PROLEGOMENA LOGICA. 

human consciousness, from what is absolute and common 
to other intelligences. 1 

In accordance with these views, we are naturally led to 
regard all the hitherto unsolved problems of Metaphysics 
as requiring to be treated from a psychological, instead of 
an ontological point of view. Instead of asking what are 
the circumstances, in the constitution of things, by virtue 
of which they present such and such difficulties and con- 
tradictions to human understanding, we must ask what are 
the circumstances of the human understanding itself, by 
virtue of which a distinction exists between the conceiva- 
ble and the inconceivable. Such, in fact, was the revolu- 
tion introduced by Kant into metaphysical speculation ; a 
revolution which he aptly compares to that effected in 
Astronomy by Copernicus, when he thought of investigat- 
ing the apparent motion of the heavens from the side of 
the spectator, instead of from that of the objects. The 
advantages of such a treatment are obvious. From the 
objective view, we obtain only the fact that certain ques- 
tions have up to the present time remained unsolved. 
From the subjective view, we learn why they are insoluble; 
and the answer to this question determines the laws and 
limits of thought. The abuse of the method appears in 



1 Truth relative to no intelligence is a contradiction in terms, as it implies 
a relation existing after one of the correlatives has been annihilated. 
Our only possible notion of absolute truth is a truth relative to all intelli- 
gences. If all truth is subjective which implies a cognitive power, Omnis- 
cience itself has but subjective truth. " Aux termes de la philosophie 
de Kant," says M. Cousin, " la raison divine serait done aussi frappee de 
subjeetivite, par cela merae que cette raison reside dans un sujet deter- 
mine qui est Dieu." (Lecons sur Kant, p. 350.) Within the limits of hu- 
man knowledge the same principle is allowed by Kant himself: " so bedeu- 
tet die objective Giiltigkeit des Erfahrungsurfheils nichts anders, als die 
nothwendige Allgemeingiiltigkeit desselben." — Prolegomena, § 18. 



PROLEGOMENA LOGICA.. 81 

the attempts of the successors of Kant, especially of Schel- 
ling and Hegel, to construct a philosophy of the absolute 
from the subjective side, by denying in certain relations 
the validity of those laws of thought which they acknowl- 
edge in others, and endeavoring thereby to do away with 
relation in consciousness altogether. Such a system, with 
whatever ability it may be constructed, carries in its funda- 
mental conception the germ of its own refutation. It 
commences by giving the lie to consciousness ; it proceeds 
by dividing the human mind against itself, the understand- 
ing against the reason, and the reason against the under- 
standing ; it ends by leaving no test by which its own truth 
can be determined. But the philosophy of Kant is like the 
spear of Achilles, and possesses virtue to heal the wounds 
which it has itself inflicted. While it is impossible to deny 
the lineal descent of the philosophy of Schelling and of 
Hegel from a one-sided view of Kantian principles, it is 
equally clear that the only satisfactory refutation of the 
extravagances of that philosophy must be based on a sober 
acknowledgment of those laws and limits of the mental 
faculties which Kant has been mainly instrumental in 
pointing out. 

We must admit, then, that our present faculties are 
trustworthy guides to that portion of knowledge which 
God designs us to attain to in our present state ; that the 
laws to which these faculties are subjected, though perhaps 
not absolutelv binding on things in themselves, are bindinc: 
upon our mode of contemplating them ; that, while we 
obey these laws, we seek after truth, according to our kind 
and in conformity with the end of our intellectual being ; 
and that, when we neglect them, we abandon ourselves to 
every form of error ; or, rather, we lose all power of dis- 
cerning between error and truth ; we commence by an act 



82 PROLEGOMENA LOGIOA. 

of intellectual suicide, and construct a system which, by 
virtue of its fundamental principle, must disclaim all supe- 
riority over, and decline to combat with, any rival theory ; 
its sole claim to attention being, that it may, for aught we 
know, be true or false, or both, or neither. 

To apply these principles to the question with which we 
commenced : Among the limitations to which even om- 
nipotence is regarded as subject, none is of older birth, or 
has been more frequently alleged, than the impossibility of 
undoing an act already done, 

fxouov yap avrov nal Qehs (TTeptcrKeTai, 
ayevrjTa iroielu au<J av y Treirpay/uLeva. 

Now, it may be that Time and Space are, as Kant main- 
tains, merely subjective conditions of human sensibility. 
As such, they limit the whole exercise of human thought. 
But the limits of the thinking faculty are limits of things 
as objects of thought only; and beyond that sphere we 
know nothing. It may be that the whole distinction of 
past, present, and future, has no place relatively to other 
intelligences than ours. Still, that distinction continues to 
influence all human thought ; and every act, as an object 
of thought, must be regarded as taking place according to 
the conditions of temporal succession. If we cease to re- 
gard it in this light, we do not extend our knowledge, but 
abandon the problem as (humanly speaking) unthinkable. 
The limitation, then, is not of omnipotence in itself, but 
of all power as the object of human thought. 1 The ulti- 

1 This distinction is drawn by Locke, in his Second Reply to the Bishop 
of Worcester. " But it is further urged, that we cannot conceive how 
matter can think. I grant it : but to argue from thence that God, therefore, 
cannot give to matter a faculty of thinking, is to say God's omnipotency 
is limited to a narrow compass, because man's understanding is so; and 
brings down God's infinite power to the size of our capacities." 



PROLEGOMENA LOGICA. 83 

mate consequence of this admission will be, that the un- 
limited is not an object of human thought at all. 1 It may 
be an object of human belief ] but the two provinces are 
not coextensive. 

So again with reference to the impossibility of reversing 
a necessary truth, such as those of Geometry. To whom 
is the problem to construct a triangle, one of whose sides 
shall be greater than the other two, " unmeaning ? " 
Clearly to the geometer, whose science has already shown 
him the necessary truth of a contradictory proposition. 
By a law of thought, he is compelled to deny that two 
contradictory assertions can be true at the same time. 
Why they may not both be true at different times, — why 
a mathematical proposition once demonstrated is held al- 
ways and everywhere true, and its contradictory always 
and everywhere false ; while other truths, however certain 
at present, are allowed only to a limited extent under 
temporal or local restrictions, — requires some further con- 
sideration. 

Necessity is the result of law, and law implies an agent 
whose working is regulated thereby. 2 But it is a law only 
to that which works under it : to an observer, who sees 
the results of the law without being subject to its influ- 
ence, it is no more than a fact evidenced by or inferred 
from sensible observation, and can never obtain higher 
value than that of a generalization from a more or less ex- 
tended experience. Hence arise two very different kinds 



1 See the admirable Article on M. Cousin's Philosophy hy Sir W"m. Ham- 
ilton, Discussions, p. 1. 

2 " All things that are have some operation not violent or casual 

That which doth assign unto each thing the kind, that which doth moder- 
ate the force and power, that which doth appoint the form and measure 
of working, the same we term a Law." — Hooker, JE. P. i. 2. 



84 PROLEGOMENA LOGICA. 

of necessity, the results respectively of laws of the ego and 
of the non-ego /* of laws under which I feel myself com- 
pelled to think, and of laws under which I see other 
agents invariably working. These two it is essential to all 
sound thinking to distinguish from each other ; and the 
more so, inasmuch as they have been perpetually con- 
founded together. ' The distinctive features of each have 
been overlooked by the disciples of opposite schools. 
By one party, laws of thought have been degraded to 
generalizations from experience; by another, empirical 
laws have been invested with the character and authority 
of original principles of mind. 2 And yet, apart from the 
psychological tenets of any particular school, it would 
seem as if a distinctive criterion might a priori be deter- 
mined, from a mere analysis of the notion of law and its 
operation. 

Setting aside, for an instant, the question how the mind 
of man is actually constituted, let us suppose an intelligent 
being, subject to laws under which he is compelled to 
think, and placed in the midst of a world of material 

1 It is much to be wished that these expressions, or some equivalent, 
were more naturalized in English philosophy. In Germany and France 
they are fully established as technical terms, and the foundation of the 
most important distinctions in mental science. In adopting here the Latin 
expressions instead of English equivalents, I have been gnided by the au- 
thority of Sir W.Hamilton, Reid's Works, p. 100, supported by that of Mr. 
Hallam, Literature of Europe, vol. ii. p. 436. (Second edition.) The latter 
observes, of the term Ego, " It seems reasonable not to scruple the use of 
a word so convenient, if not necessary, to express the unity of the con- 
scious principle. If it had been employed earlier, I am apt to think that 
some great metaphysical extravagances would have been avoided, and 
some fundamental truths more clearly apprehended." 

2 The opposite theories of Dr. Whewell and of Mr. Mill, on the nature 
of axiomatic principles, exhibit the extreme views in a remarkable de- 
gree. See Appendix, note A. 



PROLEGOMENA LOGICA. 85 

agents, subject to laws under which they must act. What 
would be the distinctive character presented to his mind 
by these respective laws of himself and of the world with- 
out ? The laws of the planetary motions are absolutely 
binding on the moving bodies themselves, independently 
of the existence of astronomical science. But it is optional 
with an intelligent being to study astronomy or not ; and, 
when he does so, he observes, as matter of fact, how such 
laws influence their own subordinate agents ; but he does 
not himself become an agent under their influence. As facts 
of his experience, 1 they are known solely in and through his 
observation ; as laws within their own sphere, they are in- 
dependent of his knowing aught about them. But the 
laws of his mind come into operation as laws when the act 
of thinking commences, and are binding, not on this or 
that class of physical phenomena, but upon the thinker 
himself, in the contemplation of all of them. Hence it is 
not optional with him whether he will think according to 
these or other conditions. Choose what object of study he 
will, he cannot think at all, he cannot conceive his liberty 
of choosing, without being ipso facto under their influ- 
ence. Hence arises an obvious criterion. A law which is 
not binding on me as a thinker, may at any time be re- 
versed, without affecting my mode of observing the same 
agents under their new conditions. And I have no diffi- 
culty in conceiving such a reversal as at any moment pos- 
sible, because, antecedent to experience, I had no internal 
bias which required the recognition of the existing law 
rather than of any other. I have only to discard an ad- 

1 " Lcs verites primitives sont de deux sortes, comme les derivatives. 
Elles sont du nombre des verites de raison, ou des verites de fait. Les 
ve'rites de raison sont neeessaires, et celles de fait sont contingentes." 
— Leibnitz, Nouv. Essais, iv. 2. 



86 PROLEGOMENA LOGICA. 

ventitious knowledge. But the reversal of a necessary law 
of thought, supposing that there are such, is, from the 
nature of the case, inconceivable; for conception is itself 
the servant of the law, and, ex hypothesis cannot rebel 
against it. I cannot by an act of thought annihilate the 
conditions by which all thought is governed. I can, indeed, 
admit the possibility that there may be other beings think- 
ing under other laws; but I can form no positive con- 
ception of their nature. Such a supposition is not thought, 
but its negation. A mind cannot think by other laws than 
its own. 

Now, how far is this hypothesis supported by facts ? Is 
it a matter of fact, that men are acquainted with certain 
truths which they acknowledge to be necessary only while 
the present laws of nature remain in force, and which they 
can conceive as reversible at any moment, and others 
which they are compelled to regard as necessary under all 
circumstances of which they are capable of thinking? Is 
it a matter of fact, that men do not attribute the same 
necessity and universality to physical as to mathematical 
truths ? Do they not acknowledge that, while the laws of 
the physical world continue as they are, seed-time and 
harvest, and cold and heat, and summer and winter, and 
day and night, shall never cease ; and yet, have they any 
difficulty in conceiving the earth's motion stopped by some 
superior power, and one-half of the globe left from that 
time forth in perpetual daylight? 1 Or do they see the least 

1 "Tous les exemples qui confirment une verite generate, de quelque 
norabre qu'ils soient, ne suffisent pas pour etablir la necessite' universelle 
de cette meme verite : car il ne suit pas, que ce qui est arrive arrivera tou- 
jours de meme. Par exemple, les Grecs et les Romains et tous les autres 
peuples ont toujours remarque, qu'avant le decours de vingt quatre heures 
le jour se change en nuit, et la nuit en jour. Mais on se seroit trompe si 



PROLEGOMENA LOGICA. 87 

improbability, not to say impossibility, in the supposition, 
that in some remote part of space there may exist worlds 
in which the alternations of the seasons have no place ? 
On the other hand, can they conceive the same power 
forming a triangle with more or less than two right angles ? 
Can they conceive an occurrence taking place in any por- 
tion of space without a cause ? or an object possessing 
neither of two contradictory attributes ? If such a dis- 
tinction exists, and our daily consciousness assures us that 
it does, the fact at once affords at least a strong presump- 
tion that the necessity in the one case is a necessity of 
observation only, depending on the laws of the world 
without, in the other a necessity of thought, depending on 
the laws of our mental constitution. 

But, granting that thought has its laws, how are these to 
be discovered ? Only by reflection upon the phenomena 
of actual thinking, and the restriction to which, in all 
cases, we experience it to be subject. To learn how we 
think, we must in the first place actually think ; and a 
multitude of successive acts of thought will be necessary, 
before we become aware that certain conditions are contin- 
gent, and limited to some of those acts only, while others 
are necessary, and cannot but be present in all. 1 If, there- 
fore, Experience be taken in a wide sense, as coextensive 
with the whole of consciousness, to include all of which 
the mind is conscious as agent or patient, all that it does 

Ton avoit cru, que la meme regie s'observe partout, puisqu'on a vu le con- 
traire dans le sejour de Nova Zembla. Et celui-la se tromperoit encore, 
qui croiroit, que c'est au moins dans nos climats une verite' necessaire et 
eternelle, puisqu'on doit juger, que la Terre et le Soleil meme n'existent 
pas necessairement, et qu'il y aura peut-etre un temps, oil ce bel astre ne 
sera plus avec tout son Systeme, au moins en sa presente forme." — Leib- 
nitz, Nouveaux Essais, Avant-Propos. 
1 See Hamilton on Reid, p. 772, and Cousin, Cours de PMlosopJiie, Lee. 22. 



88 PROLEGOMENA LOGICA. 

from within, as well as all that it suffers from without, — in 
this sense, the laws of thought as well as the phenomena 
of matter, in fact all knowledge whatever, may be said to 
be derived from experience} But further, experience in its 
narrower and more common meaning, as limited to the re- 
sults of sensation and perception only, 2 is, though not the 
source, the-indispensable condition of discovering the laws 
of mind as well as of matter. For, to think actually, we 
must think about something; this something, the object- 
matter of thought, whatever it may be, must in the first 
instance be supplied through the medium of the senses ; 
for thought itself does not become an object of thought 
till after it has been called into exercise by objects pre- 
sented from without. 3 But while the material or external 
element varies with every successive act of thought, the 
formal or internal remains the same in all ; and thus the 
necessary law, binding on the thinker in every instance, is 
distinguished from the contingent objects, about which he 
thinks on this or that occasion. 

The last consideration necessitates a further division of 
those truths which have already been distinguished as 
necessary, and therefore not derived from experience. 
While we maintain that all necessary truths must have 

1 In this extended sense, Wolf derives the principle of contradiction 
from experience : "Experiri dicimur, quicquid ad perceptiones nostras at- 
tenti cognoscimus. Solem lucere cognoscimus ad ea attenti, quas visu per- 
cipimus. Similiter ad nosmet ipsos attenti cognoscimus, nos non posse 
assensum praebere contradictories, v. gr. non posse sumere tanquam verum, 
quod simul pluat vel non pluat."— Ph. Bat. § 664. Here it should be ob- 
served that perception is used in a wider sense than that to which Reid and 
the Scottish Philosophers after him restrict it. 

2 'Ek jxkv ovv ala&fio-eoos yli/ercu fj.vr]/xr}, 4k 5e fxwi]fj.ris iro\Xa.Kis tov alnov 
yivo/j.4v7)s e fiir e i p i a. — Arist. Anal. Post. ii. 19. 

3 Cf. Arist. Be Anima, iii. 4, 7. 



PROLEGOMENA LOGICA. 89 

their origin in the constitution of the mind itself, and are 
virtually prior to all experience, they cannot all of them 
be referred to Laws of Thought, properly so called. For 
thought, as thought, cannot be limited to any special class 
of objects : its laws must operate in all cases alike, what- 
ever be the matter on which it is engaged. That every 
triangle has its angles equal to two right angles, is indeed 
a necessary truth ; but it is true of triangles only, and can- 
not be applied to any other object. But that the same 
subject cannot possess contradictory attributes, is a princi- 
ple equally applicable to the objects of geometrical dem- 
onstration and to the most contingent facts of sensible 
experience. It is equally certain, that no man can at 
once be standing and not standing, as that the angles of a 
triangle cannot be both equal and unequal to two right 
angles. Hence the criterion of absolute necessity, though 
valid as far as it goes, is not adequate to determine the 
whole question. It serves to distinguish judgments a 
priori from judgments of experience : it does not distin- 
guish between different classes of the former, nor explain 
their several relations to the mind, which is the common 
source of all. Of the various judgments which have been 
enumerated by philosophers as necessary truths, it will be 
sufficient for our present purpose to select three classes, 
which may be severally distinguished as Mathematical, 
Metaphysical, and Logical Necessity. All these, being in 
different ways regarded as absolutely and universally ne- 
cessary, must be considered as in different ways dependent 
on laws of our mental constitution. From all must be 
distinguished what is commonly called Physical Necessity, 
or belief in the permanence of Laws of Nature. The 
several distinctions may be represented by the following 

questions : 

8* 



90 PROLEGOMENA LOGICA. 

I. Why do I judge that a triangle can, under no cir- 
cumstances whatever, have its angles greater or less than 
two right angles ? 

II. Why do I judge that every sensible quality must 
belong to some subject, and that every change is and must 
be brought about by some cause ? 

III. Why do I judge that two contradictory attributes 
can, under no circumstances whatever, coexist in the same 
subject ? 

IV. Why do I judge that the alternations of day and 
night will not, under the existing circumstances of our 
globe, cease to take place ? 

The last of these obviously stands on a different ground 
from the other three. I am immediately cognizant of law 
only as I am conscious of its obligation upon myself. 
The law itself may be physical, intellectual, or moral ; but 
to know it as a law, I must know it as a condition which 
I cannot or ought not to transgress. Law, in this sense, 
as a discerned obligation, can obviously exist only in rela- 
tion to a conscious agent ; and even with regard to con- 
scious agents, other than myself, I only infer the existence 
of the law from a supposed similarity between their con- 
stitutions and my own. But, as regards unconscious 
agents, Law means no more than a constantly observed 
fact in its highest generalization. When I speak of the 
alternations of day and night as consequent on a law of 
nature, I mean no more than that the alternation has in- 
variably been observed to take place; and, when I resolve 
such alternations into the law of the earth's rotation, I 
mean only that the earth does constantly revolve on her 
axis once in twenty-four hours. Or, if I could resolve all 
the phenomena of the material world into a universal law 
of gravitation, I should obtain no more than the universal 



PROLEGOMENA LOGICA. 91 

fact, that all particles of matter in the universe do gravi- 
tate towards each other, and that certain subordinate com- 
binations of those particles present certain phenomena in 
so doing. But I have not, by this resolution, got any 
nearer to necessity ; for the gravitation of bodies in the 
inverse ratio of the square of the distance is, like the ebb 
and flow of the tides, or the elliptical orbits of the planets, 
an observed fact in the order of nature, and it is no more. 1 
3fy belief in the continuance of this observed order may 
perhaps be explained by some law of my mental con- 
stitution ; but, as thus explained, it is a law of mind, and 
not of matter. Under what circumstances certain facts 
of nature may be resolved into others, and what kinds of 
experiment and observation will contribute to this end, 
are questions which, with all their importance, are totally 
distinct from those which form the object of the present 
inquiry. 

I shall only observe here, that to call such questions a 
portion of Logic — that is, to regard the New Organon as 
a supplement to the Old, and both as forming parts of 
the same Science — is to confound two essentially distinct 
branches of knowledge, distinct in their end, in their 
means, and in their evidence. 2 " We do not enlarge the 
sciences," says Kant, " but disfigure them, when we suffer 
their boundaries to run into one another." The con- 
fusion produced in the present instance is perhaps the 
most injurious of all to sound thinking — a confusion be- 
tween the mental self and its sensible objects, the ego and 
the non-ego^ the positive and negative poles of speculative 
philosophy. 

1 See Stewart, Elements, vol. ii. eh. 2, § 4. 

2 On this distinction some excellent remarks will be found in M. Jouf- 
froy's Preface to his translation of Reid, p. 43. 



CHAPTER IY. 

ON THE PSYCHOLOGICAL CHARACTER OF MATHEMATICAL 
NECESSITY. 

It has been already observed, that whatever truths we 
are compelled to admit as everywhere and at all times 
necessary, must have their origin, not without, in the laws 
of the sensible world, but within, in the constitution of the 
mind itself. 1 Sundry attempts have, indeed, been made to 
derive them from sensible experience and constant associa- 
tion of ideas; 2 but this explanation is refuted by a cri- 
terion decisive of the fate of all hypotheses : it does not 
account for the phenomena. It does not account for the 
fact, that other associations, as frequent and as uniform, 
are incapable of producing a higher conviction than that 
of a relative and physical necessity only. And, indeed, 
this might have been expected beforehand ; for the utmost 
rigor in a law of the sensible world may furnish a sufficient 
reason why phenomena must take place in a certain man- 
ner, but furnishes no reason at all why I must think so. 

But it is one thing to recognize the operation of a men- 

1 " La preuve originaire des verites necessaires vient du seul entende- 
ment, et les autres verites viennent des experiences ou des observations 
des sens. Notre esprit est capable de connoitre les unes et les autres, mais 
il est la source des premieres, et quelque nombre d'experiences particu- 
lieres qu'on puisse avoir d'une verite universelle, on ne sauroit s'en assu- 
rer pour toujours par l'induction, sans en connoitre la nccessite par la 
raison." — Leibnitz, Nauv. Essais, 1. i. cli. 1. 

2 See, for example, Mill's Logic, vol. i. p. 305. 



PROLEGOMENA LOGICA. 93 

tal law, and another to discover the law itself. The dis- 
tinction above noticed between Mathematical, Metaphysi- 
cal, and Logical Necessity, implies, that, although the 
origin of all is to be sought for in the mind itself, they 
are in some way differently related to one or other of the 
special faculties of their common source. We must further 
inquire, what is the peculiar relation of the mind to mathe- 
matical ideas, 1 by virtue of which not merely the general 
laws of all thinking, but the special applications of those 
laws in Arithmetic and Geometry, possess a necessity 
which is not found when they are applied to concepts 
generalized from experience. How 7 is it that in some rea- 
sonings both matter and form can be furnished by the 
mind itself, while in others the form alone is from the 
mind, the matter being derived from experience ? 

Before entering upon this question, it will be necessary 
to give some account of Kant's celebrated distinction 
between Analytical and Synthetical Judgments. An An- 
alytical or Explicative Judgment contains nothing in the 
predicate but what has been already implied in the concep- 
tion of the subject. For example : since the conception 
of body implies extension, the proposition, " All bodies are 
extended," is an Analytical Judgment. Of this character 
are all propositions in which, in scholastic language, the 
predicate is said to be of the essence of the subject ; 
whether a part of the essence, as in the predication of 
genus or differentia, or the sum of the parts, as in a defini- 
tion. 2 In a Synthetical or Ampliative Judgment, on the 

1 The word idea is here used intentionally, as, in modern philosoplry, 
the most vague and indeterminate that could be selected. It would be an 
anticipation of what has yet to be determined to give any more definite 
expression. 

2 The substitution of definition for species is intentional. 



94 PROLEGOMENA LOGICA. 

other hand, the predicate adds an attribute to the subject 
which has not been already thought therein. Thus the 
proposition, " All bodies are heavy," is a Synthetical Judg- 
ment ; the attribute heavy not being thought in the mere 
conception of body. Of this kind are all propositions in 
which the predicate is said to be joined to the essence of 
the subject as a property or accident. 1 

All Analytical Judgments are formed by the mind a 
priori^ whether the notion analyzed be empirical or not. 
For the mind, having once gained this notion as a subject, 
has no occasion for any additional experience to determine 
the predicate which is already given therein. 2 Any Science 
whatever may therefore have abundance of necessary truths 
of this kind ; but such do not contribute in any way to the 
extension of our knowledge, but only to a more distinct 
consciousness of what we already possess. A Synthetical 
Judgment, on the other hand, is a positive extension of 
our knowledge, but requires for its formation something 
more than the concept which stands as its subject. All 
empirical judgments are synthetical; 3 but mathematical 
necessity requires that the mind should be able to form 
for itself synthetical judgments not dependent on experi- 
ence. 

The axioms of Geometry contain specimens of both 
kinds of judgment. Those which relate exclusively to geo- 
metrical objects, — such as, "A straight line is the shortest 
distance between two points," 4 "Two straight lines cannot 
enclose a space," "Two straight lines which, being met by 
a third, make the interior angles less than two right 

1 Sec Kant, Kritik der r. V. p. 21 ; Prolegomena, p. 16, ed. Rosenkranz. 

2 Kant, Proleg., p. 17. 

3 Kant, Kritik der r. V. p. 700; Proleg., p. 18. 

4 This is sometimes given as a definition, but it is properly synthetical. 



PROLEGOMENA LOGICA. 95 

angles, will meet if produced" — have been shown by Kant 
to be synthetical; 1 and it is with reference to these that 
he discusses the well-known question, How are synthetical 
judgments a priori possible ? But those axioms which are 
not peculiar to Geometry, the common principles of Aris- 
totle, 2 — such as, " The whole is greater than its part," 
"Things that are equal to the same are equal to each other," 
" If equals be added to equals, the sums are equal," — are ana- 
lytical. 3 The two last, indeed, may be easily shown to be 
merely various statements of the Principle of Identity, 
" Every thing is equal to itself," or, " A = A." Thus, if 
the common magnitude of the first pair of equals be rep- 
resented by A, and that of the second by B, the axiom, 
" If equals be added to equals, the sums are equal," is ex- 
pressed in the identical judgment, " A -|- B == A -(- B." 4 
The former class of axioms determine the peculiar 

1 " Dies sind die Axiome, welche eigentlich imr Grossen als solche bet- 
reffen."— Kant, Kritik der r.V. p. 143; cf. p. 703, etc.; Proleg. p. 20. Hence 
the error of Leibnitz, in maintaining that all axioms (excepting, of course, 
identical judgments themselves) may be demonstrated from definitions 
and the judgments of identity. (Opera, Erdm. p. 81.) He selects as a 
specimen the analytical judgment, "The whole is greater than its part," 
and of such his theory is correct; but no synthetical judgment can be 
proved solely from analytical premises ; and without synthetical axioms 
Geometry is impossible. 

2 Synthetical axioms are not included, as they should have been, under 
the peculiar principles (fttcu apxai)of Aristotle, which are divided into defi- 
nitions and hypotheses. With the exception of this omission, Aristotle's 
account of geometrical demonstration is far more accurate than any that 
can be found in modern philosophy before Kant. 

3 Cf. Kant, Kritik der r. V. p. 143. 

4 Dr. Whewell (Phil. Ind. Sc. vol. i. p. 134) speaks of this axiom as a 
condition of the intuition of magnitudes. This is a confusion of the com- 
mon axioms of Logic with the peculiar axioms of Geometry. Stewart 
(Elements, vol. ii. ch. 1) falls into the opposite error, regarding all the 
truths of Geometry as deduced from definitions. 



96 PROLEGOMENA LOGICA. 

character of all the conclusions of Geometry ; the latter 
have no peculiar relation to Mathematics, but depend on 
the general conditions of all thinking whatever, and have 
therefore a logical, not a mathematical necessity. The 
whole question of the superior necessity of Geometry to 
Physical Science depends upon the manner in which we 
account for the origin of the synthetical axioms relating 
to magnitudes as such. As an instance, we may take the 
proposition, " Two straight lines cannot enclose a space." 

An eminent writer of the present day has labored hard 
to prove that this principle is nothing but a generalization 
from experience, and, consequently, that our belief in 
the superior necessity of mathematical as compared with 
physical truths is a mere self-deception. He lays much 
stress on one of the characteristic properties of geometrical 
forms, their capacity of being painted in the imagination 
with a distinctness equal to reality; in other words, the 
exact resemblance of our ideas of form to the sensations 
which suggest them. 1 But while it is impossible to deny 
the ability with which Mr. Mill combats the notion of an 
a priori necessity in Mathematics, it is impossible to assent 
to an argument which contradicts the direct evidence of 
consciousness. Nor does this reasoning against Doctor 
"Whewell, however powerful as an argumentum ad homi- 
nem, meet the real question at issue. What is required 
is to account, not for the necessity of geometrical axioms 
as truths relating to objects without the mind, but as 
thoughts relating to objects within. Mathematical judg- 
ments are true of real objects only hypothetically. If 
there exist anywhere in the world a pair of perfect 
straight lines, those lines cannot enclose a space. But 
if such lines exist nowhere but in my imagination, it is 

1 Mill's Logic, vol. i. p. 309. 



PROLEGOMENA LOGICA. 97 

equally the case that I cannot think of them as invested 
with the contrary attribute. That which is to be accounted 
for is, not the physical fact that certain visible objects 
possess certain properties, but the psychological fact that, 
in the case of geometrical magnitudes, I am compelled to 
invest imagined objects with attributes not gained by 
mere analysis of the notion under which they are thought; 
— a compulsion of which I am not conscious with regard 
to the most uniform associations of phenomena within the 
field of sensible experience. A sensible object may have 
been familiar to me from childhood ; but, suppose the 
external reality destroyed, I can assert nothing with 
certainty of its imaginary representative, except what is 
contained in the concept itself. So long as I have to 
conform my judgments, not to the actual laws of the 
existing course of nature, but to the possible conditions 
of an imaginary state of things, I have no difficulty in 
attributing contradictory attributes successively to the 
same object. I may imagine the sun rising and setting 
as now for a hundred years, and afterwards remaining 
continually fixed in the meridian. Yet my experience 
of the alternations of clay and night has been at least 
as invariable as of the geometrical properties of bodies. 
I can imagine the same stone sinking ninety-nine times 
in the water, and floating the one-hundredth; but my 
experience invariably repeats the former phenomenon 
only. Whereas, in the case of two straight lines, which, 
so far as they are objects of experience, stand only on a 
level with the above and similar instances, the mind finds 
itself compelled to assert as necessary one attribute, not 
contained in the concept, and to reject its contradictory 
as impossible. 

The possibility of forming synthetical judgments a priori 
9 



US PROLEGOMENA LOGICA. 

in Geometry admits of only one adequate explanation, 
viz., that the presentative intuition, as well as the repre- 
sentative notion, is derived from within, not from without; 
in other words, that both the matter and form of the 
judgment are determined subjectively. If it can be shown 
that the object of which pure Geometry treats is not 
dependent on sensibility, but sensibility on it ; that it is 
a condition under which alone sensible experience is pos- 
sible, it is obvious that its characteristics must accompany 
all our thoughts concerning any possible object of such 
experience; that its laws niust be equally binding upon 
the imaginary representation as upon the sensible percept : 
for, abstract as we may from this or that particular phe- 
nomenon of experience, we are clearly incompetent to de- 
prive it of those conditions under which alone experience 
itself is jmssible. 

Such a condition is furnished to us by the intuition of 
Space. That this is a subjective condition of all sensible 
perception, and not a mere empirical generalization from a 
special class of phenomena, is evident from the fact that 
it is impossible, by any effort of thought, to contemplate 
sensible objects, save under this condition. We may 
shift our attention at will from this object to that; but 
we can think of none save as existing in space. We 
may conceive the whole world of sensible phenomena 
to be annihilated by the fiat of Omnipotence; but the 
annihilation of space itself is beyond the power of thought 
to contemplate. That things in themselves must exist in 
space, and, as such, must be so presented to every jjossible 
intelligence, is more than we may venture to affirm ; but 
this much is certain, that man, by a law of his nature, 
is compelled to perceive and to think of them as so ex- 



PROLEGOMENA LOGICA. „W 

Upon this law of the mind depends the certainty of 
geometrical axioms as thoughts, though not as truths. 
The peculiar figures of space must, indeed, be originally 
suggested empirically, from observation of the actual fig- 
ures of body ; but this experience is still subject to the 
same condition. Bodies cannot be perceived or imagined, 
but in space : bodies of this or that figure cannot be 
perceived or imagined, but as occupying a similarly figured 
space. The modifications originally suggested by the for- 
mer become an object of thought as existing in the latter; 
and the features exhibited now and here in the one, we 
are compelled to think as existing always and everywhere 
in the other. 

The sensationalist is therefore, in a certain sense, right 
in deriving geometrical axioms from experience. It must 
be conceded to him that, had we never seen two straight 
lines, had we never observed that as a matter of fact they 
did not in that particular instance enclose a space, we 
should never have arrived at the conviction that they 
cannot do so in any instance. But this is equally true 
of any product of the imagination. If I had never seen 
separately the upper parts of a man and the lower parts 
of a horse, I could not unite them together in the fantastic 
image of a centaur. If I had never seen a black object, I 
could not combine that color with a known form, so as to 
produce the imagination of a black swan. But why is it 
that in the one case I find no difficulty whatever in going 
beyond or against the whole testimony of my past experi- 
ence, while in the other such transgression is altogether 
out of my power? Experience has uniformly presented 
to me a horse's body in conjunction with a horse's head, 
and a man's head with a man's body; just as experience 
has uniformly presented to me space enclosed within a 



100 PROLEGOMENA LOGICA. 

pair of curved lines, and not within a pair of straight ones. 
Why do I, in the former case, consider the results of my 
experience as contingent only and transgressible, confined 
to the actual phenomena of a limited field, and possessing 
no value beyond it ; while, in the latter, I am compelled 
to regard them as necessary and universal? "Why can I 
give in imagination to a quadruped body what experience 
assures me is possessed by bipeds only ? And why can I 
not, in like manner, invest straight lines with an attribute 
which experience has uniformly presented in curves? 

Can it be said that the ideas in the latter case are con- 
tradictory, and that their union is therefore forbidden by 
the laws of formal thinking ? By no means. Straight and 
curved, viewed merely as objects of sense, are opposed only 
as black and white, or as biped and quadruped / they can- 
not, that is, be thought as existing at the same time in the 
same subject : but that property which experience testifies 
to have universally accompanied curved lines is not, merely 
by virtue of that experience, more incompatible with 
straight ones than the head which has uniformly accom- 
panied a biped body is incompatible with a quadruped 
one ; or than the form which experience has uniformly con- 
nected with a white surface is incompatible with a black 
one. Nor does the impossibility arise from any defect in 
the simple ideas, such as exists in the case of a man who 
can form no idea of a color which he has never seen. We 
have all the simple ideas, or combinations of simple ideas, 
which experience can give : man's head and horse's body, 
in the one case ; straight lines and space enclosed, in the 
other. Why is not the latter conjunction as easy to the 
imagination as the former? 

That it is not so, is a matter not of this or that theory, 
but of psychological fact ; and, as such, requires explana- 



PROLEGOMENA LOGICA. 101 

tion, under any theory whatever. In fact we may demand, 
as a sine qua non, of every hypothesis concerning the 
character of human knowledge, that it shall accept and 
account for this fact, instead of neglecting or denying it. 
Only two theories can be mentioned as having fairly at- 
tempted to fulfil this condition. The one is that of Leib- 
nitz, who treats mathematical principles as mere analytical 
judgments, dependent on the laws of formal thought. On 
this supposition, the distinction between Logical and 
Mathematical necessity vanishes altogether. 1 But the 
solution, though applicable to the general axioms which 
Geometry, in common with all other Sciences, tacitly or 
openly presupposes in so far as it contains reasoning at all, 
fails when applied to those on which all that is especially 
geometrical depends. By no mere analytical process, as 
Kant has shown, 2 can the conception of not enclosing a 
space be elicited from that of two straight lines. In this, 
and all similar principles, the predicate of the proposition 
is not developed out of, but added to, the subject. 

The other, and far more satisfactory, solution, is that of 
Kant himself. Whatever we are compelled to regard as 
necessary, must be so in consequence of laws, not of the 
object, but of the subject. But there are subjective laws 
of the presentations of sense, as well as of the representa- 
tions of thought. We can perceive only as permitted by 
the laws of our perceptive faculties, as we can .think only 
in accordance with the laws of the understanding. If, then, 
by a law of my sensibility, I am compelled to regard all 
external objects as existing in space, any attributes which 
are once presented to me as properties of a given portion 
of space, the same must necessarily be thought as existing 

1 Opera, ed. Erdmann, p. 81. 2 Prolegomena, § 2. 

9* 



102 PROLEGOMENA LOGIC A. 

in all space, and at all times. For to imagine a space in 
which such properties are not found, would not be to im- 
agine merely a different combination of sensible phenom- 
ena, such as continually takes place without any change in 
the laws of sensibility ; it would be to imagine myself as 
perceiving under conditions other than those to which, by 
a law of my being, I am subjected. The attempt to realize 
such imagination is not a new train of thinking ; it is the 
refusal to think at all. It does not inquire what new 
objects may possibly be presented to my present faculties; 
it requires me to determine how objects may appear to a 
being whose faculties are differently constituted from mine. 
Thought, as has already been observed, is representative, 
and can only be exercised on objects presented to it. It 
is therefore restricted by the conditions under which alone 
such presentation is possible. If I am to exercise my 
thought on sensible objects at all, I must think of such 
objects under such determinations as the conditions of my 
sensibility require. 

Geometrical principles cannot, therefore, properly be 
called laws of thought, inasmuch as they do not govern 
every operation of the thinking faculty, but only regulate 
the application of thought to a special class of objects. But 
they are laws relative to the subjective condition of one 
portion of our intuitions — those, namely, which are pre- 
sented to the senses — the condition of their presentation 
being Space. But a condition is discernible only in con- 
junction with that of which it is the condition. Space, 
therefore, and its laws can be made known to conscious- 
ness only on the occasion of an actual experience of sense. 
Hence the twofold character of geometrical principles : 
empirical, as suggested in and through an act of experi- 



PROLEGOMENA LOGICA. 103 

ence ; necessary, as relating to the conditions under which 
alone such experience is possible to human faculties. 1 

The same considerations will explain another important 
feature of geometrical judgments, in which they represent 
a striking contrast to truths properly called empirical. 
Imagination plays its part in both ; but in the former case 
it determines, in the latter it is determined by, the phe- 
nomena given in experience. The mental image which I 
can form of this or that individual possesses more or less 
of truth and reality, as it represents with more or less 
accuracy the features of the sensible object ; just as the 
value of a portrait depends on the accuracy with which it 
represents the features of the original. The imagination, 
again, may of itself form new combinations of attributes; 
but these also are hypothetically regarded as real or fic- 
titious, according as we may or may not hereafter discover 
such combinations to exist in sensible objects. But in 
Geometry the case is reversed. Its propositions are 
primarily and necessarily true of objects existing in the 
imagination ; they are only secondary and hypothetically 
true of sensible objects, in so far as they conform to the 
imaginary model. If there is such a thing in the visible 
world as a perfect triangle, its angles are equal to two 
right angles. But if there is not, the proposition is still 
true of the triangle as it exists in my imagination. And 

1 This character of the special axioms of Geometry is remarkably ex- 
pressed in the language of Aristotle. For example: cua&Tjcris, ou% v rwu 
Idiwit, a\?C o'ia al<r&av6fji.€&a on to iv to7s /j.a^T]ixaTiKO?s scrxarov rpiyco- 
vov. — Mh. Nlc. vi. 9. And again : Tavra 8* ia-rlu olov opav r fj vo^azi. 
— Anal. Post. i. 12. With which may be compared the language of Kant, 
Logik, § 35: " Die ersten konnen in der Anschauung dargestellt werden." 
Had Aristotle been aware of the distinction between the analytical and the 
synthetical axioms, he might almost have anticipated Kant's view of the 
whole question. 



104 PROLEGOMENA LOGICA. 

the whole of Geometry, as a speculative science, would be 
unaffected by the annihilation of every material square 
or triangle in existence, whatever might become of its 
merely approximate applications to purposes of practical 
utility. Whereas, the truths of Zoology, or Botany, or 
Mineralogy, are dependent entirely on the existence of 
animals, or plants, or minerals, not as images within the 
mind, but as entities without. The cause of this distinc- 
tion is manifest from what has been said above. The 
truths of Geometry, though subsequent to, are not con- 
sequent on, experience : they relate not to the empiri- 
cal figures of body, but to the figures of that space upon 
which sensible experience is dependent. They are there- 
fore unaffected by the destruction of the visible bodies, 
and could only become fictitious by the annihilation of 
space itself. But the truths of Physical Science depend 
upon experience alone : they are true of the objects only 
as actually presented to the senses ; and their reality de- 
pends entirely on the real existence of the sensible type. 

As Geometry is a science of necessary truths relating to 
continuous quantities or magnitudes, so Arithmetic is a 
science of necessary truths relating to discrete quantities 
or numbers. The two sciences, however, present some 
important features of distinction. Almost all the truths 
of Geometry are deductive. It contains very few axioms, 
properly so called, i. e., synthetical judgments, derived im- 
mediately from the intuition of space ; and its processes 
consist in the demonstration of a multitude of dependent 
propositions, from the combination of these axioms with 
analytical principles. On the other hand, the fundamental 
operations of Arithmetic, Addition, and Subtraction, 1 pre- 

1 " Though in some things, as in numbers, besides adding and subtract- 



PROLEGOMENA LOGICA. 105 

sent to ns a vast number of synthetical judgments; each 
of which, however, is derived immediately from intuition, 
and cannot, by any reasoning process, be deduced from any 
of the preceding ones. 1 Pure Geometry cannot advance a 
step without demonstration ; and its processes are there- 
fore all reducible to the syllogistic form. Pure Arithmetic 
contains no demonstration; and it is only when its calculus 
is applied to the solution of particular problems that rea- 
soning takes place, and the laws of syllogism become ap- 
plicable. It is not reasoning which tells us that two and 
two make four; 2 nor, when we have gained this proposi- 
tion, can we in any way deduce from it that two and four 
make six. We must have recourse, in each separate case, 
to the senses or the imagination, and, by presenting to 
the one or the other a number of individual objects corre- 

ing, men name other operations, as multiplying and dividing, yet they are 
the same: for multiplication is but adding together of things equal; and 
division, but subtracting of one thing, as often as we can." — Ilobbes, Levi- 
athan, part i. ch. 5. 

1 Subtraction may be demonstrated from Addition, if all the truths of 
the latter be supposed given, or vice versa; though it is simpler to regard 
Subtraction as an independent process of denumeration, as is done by Con- 
dillac, Langue des Calculs, ch. i. But no result of either can be derived 
from a preceding result of the same operation. 

2 Nothing, at first sight, can appear more satisfactory than Leibnitz's 
proof of this proposition. Nouv. Essais, 1. iv. ch. 7. But that demon- 
stration assumes the definitions of the higher numbers (2 is 1 + 1 ; 3 is 1 
+ 1 + 1, etc.), and this, as will hereafter appear, is in fact begging the 
whole question. The real point at issue is not whether 4 and 2 + 2 are at 
bottom identical, so that, both being given, an analysis of each will ulti- 
mately show their correspondence; but whether the former — notion, defini- 
tion and all — is contained in the latter. In other words, whether a man 
who has never learned to count beyond two, coidd obtain three, four, five, 
and all higher numbers, by mere dissection of the notions which he pos- 
sesses already. This remark applies also to Stewart (Elements, vol. ii. ch. 
1), and to Hegel's attempted critique of Kant ( Werke, vol, v. p. 275). 



106 PROLEGOMENA LOGIC A. 

sponding to each term separately, envisage the resulting 
sura. 1 The intuition thus serves nearly the same purpose 
as the figure in a geometrical demonstration ; with the ex- 
ception, that in the latter case the construction is adopted 
to furnish premises to a proposed conclusion, while in the 
former it gives us a judgment which we have no imme- 
diate purpose of applying to any further use. 

An apparent objection, which meets us at the outset, 
must not be left unnoticed. If the results of Arithmetic 
are altogether intuitive, how is it that they extend to cases 
of which sense has never furnished us with the occasion 
of judging? I may have never seen a thousand objects 
of any kind together, yet I am as fully convinced that 976 
+ 24 === 1000, as I am that 2 + 2=4, of which I see 
instances every day of my life. And, even if I have seen 
examples of the former as well as of the latter, how far 
does the observed fact help in the formation of the judg- 
ment? Is my sight so acute that I can distinguish at a 
glance a group of 1000 objects from one of 999? Can I 
then, in any case, be said to have seen the fact verified ? 
And if not, how is it that I do not merely know that what 
I have seen in a single case must be true universally, but 
even can be assured of the necessity of truths which I 
have never accurately observed in any actual instance? 

This objection is based on a confusion of intuition in 
general with the special presentations of sight. 2 When the 

1 See Kant, Kritik der r. V. p. 703. I have availed myself of the term 
envisage, as the best English equivalent that has yet been proposed to the 
German anschauen, a word which is applied generally to any presentation 
of individual objects in sense or imagination. Etymologically, both the 
German and the English word are drawn from the sense of sight only. 
If uniformity alone were to be consulted, the substantive Anschauung, usu- 
ally translated intuition, should be rendered by envisaging. 

2 A confusion to which Kant himself has perhaps, in some degree, con- 



PROLEGOMENA LOGICA. 107 

propositions of Arithmetic are said to be intuitive, it does 
not follow that their truth must have been observed in 
visible instances ; that we must have seen, for example, 
that two and three make five, in lines, or pebbles, or the 
fingers of the hand. It implies only that we must have 
perceived the truth of the proposition in some individual 
series, it may be of visible objects, it may be of audible 
sounds, it may be of states of our own minds present to 
internal observation. In none of these cases do we deal 
with representative concepts, but with individual objects 
presented to the external or internal sense. 

Now, how, as a matter of fact, are arithmetical judg- 
ments usually formed ? We see inexperienced calculators 
arrive at their results by running through, orally or men- 
tally, the several units of the numbers to be added together. 
If we do not remember that 18 and 7 make 25, as readily 
as that 2 and 2 make 4, we supply the defect by summing 
up severally 19, 20, 21, etc. The artificial aids to which 
we have recourse in larger sums, by adding up, for instance, 
the corresponding digits in separate columns, are but ab- 
breviated steps of the same process. 

Setting aside, as belonging to art rather than science, all 
those methods whose aim is merely to extend or facilitate 
already existing processes, the psychological foundation 
of Arithmetic is to be found in the consciousness of suc- 
cessive mental states ; and its earliest actual process con- 
sists in giving names to the several members of the series. 
Such a process, which may be denominated natural, as 
distinguished from artificial numeration, would proceed 
steadily forward, from one member arbitrarily selected as 

tributed, by representing (Proleg. § 2) five visible points as the intuition 
of the number; thus by implication connecting Arithmetic with space 
rather than with time. 



108 PROLEGOMENA LOGICA. 

the starting-point, acknowledging no relation between the 
several steps beyond that of succession to its predecessor, 
until the computation ceases from the inability of the 
memory to carry on the series. Such a system, however 
limited in its practical results, would rest on precisely the 
same foundation as the more perfect methods which art 
has supplied us, and will, consequently, contain all the data 
required for determining the nature of the necessary truths 
of Arithmetical Science. 

As Arithmetic, as well as Geometry, contains such truths, 
it must be equally regarded as founded on an internal law 
or condition of our mental constitution. This condition 
is that of Time, a condition which governs not merely our 
external perceptions, but our universal consciousness of all 
that takes place within or without ourselves. Every suc- 
cessive modification of the conscious mind can be made 
known to us only as a change of state ; a change which is 
only possible under the condition of succession in time, — 
a transition from an earlier to a later phase of conscious- 
ness. Of Time, as an absolute existence, we cannot form 
any idea whatever : it is made known to us only as the 
condition or form of successive states of consciousness. 
To ask, therefore, whether Time has any existence out of 
our own minds, is, in the only intelligible mode of putting 
the question, to ask whether other orders of intelligent 
beings are subject to the same conditions of intelligence 
as ourselves ; whether they, like us, are conscious of vari- 
ous mental states, one succeeding another. Put in this 
form, the question is sufficiently intelligible, but obviously 
one which we have no data for determining ; put in any 
other form, it is absolutely void of meaning; it contains not 
the material for thought, but only a negation of all think- 
in 2f whatever. 



PROLEGOMENA LOGICA. 109 

It might indeed be argued, with some show of proba- 
bility, that the condition of successive consciousness is 
essentially the condition of a finite and imperfect intelli- 
gence, consequent only upon its very limited power of 
simultaneous consciousness. 1 The scholastic doctrine of 
an eternal JYdio, or nunc stems, so contemptuously treated 
by Hobbes, in this respect contains assuredly no prima 
facie absurdity. 2 The error of such speculations is of an- 
other kind. It consists in mistaking the negation of all 
thought for an act of positive thinking. As our whole 
personal consciousness is subject to the condition of suc- 
cessiveness, we can form no positive notion of a different 
state : we only know that it is something which we have 
never experienced. The nature and attributes of an Infi- 
nite Intelligence must be revealed to us in a manner ac- 
commodated to finite capacities. How far the accommo- 
dation extends, we have no means of determining, as we 
cannot examine the same data with a different set of facul- 
ties. The importance of this distinction between positive 

1 Vide Boeth. De Consol. Phil., lib. v. pros. vi. 

2 It is surprising to see how near some of the earlier views on this point 
approached to, without actually arriving at, the doctrine of Kant. Had 
the question been considered subjectively as well as objectively, on the 
psychological as well as on the metaphysical side, the most important 
conclusion of the Critical Philosophy would have been anticipated. When 
Hobbes, in his controversy with Bramhall, said, " I never could conceive 
sax ever-abiding now," he was right; but he was wrong in supposing that 
this was decisive of the point at issue. "We can only conceive in thought 
what we have experienced in presentation ; and all our past pi-esentations 
have been given under the law of succession. But this does not enable us 
to decide Avhat may be the condition of other than human intelligences. 
In this respect, the remark of Bramhall is exactly to the purpose: 
" Though we are not able to comprehend perfectly what God is, yet we 
are able to comprehend what God is not; that is, he is not imperfect, 
and therefore he is not finite." Reid (Intell. Powers, Essay hi. ch. 3) treats 
the nunc starts as a contradiction, which it is not. 

10 



110 PROLEGOMENA LOGICA. 

and negative thinking will be more closely examined here- 
after. 

But, to return to the question of mathematical necessity : 
To construct the whole science of Arithmetic, it is only 
requisite that we should be conscious of a succession in 
time, and should be able to give names to the several 
members of the series. And since in every act of con- 
sciousness we are subject to the law of succession, it is 
impossible in any form of consciousness to represent to 
ourselves the facts of Arithmetic as other than they are. 
To the art, not to the science, of Arithmetic belong all the 
methods for facilitating calculation which imply anything 
more than the mere idea of succession. Such a method, 
and a powerful one, is afforded by the invention of Scales 
of Notation, in which, to the idea of succession, is added 
that of recurrence ; the series being regarded as commenc- 
ing again from a second unit, after proceeding continuously 
through a certain number of members, ten for example, as 
in the common system. Hence we are enabled to repeat 
over again, in the second and subsequent decades, the 
operations originally performed in the first, and thus indef- 
initely to extend our calculus in the form of a continually 
recurring series ; but the calculus, though thus rendered 
infinitely more efficacious as an instrument, remains in its 
psychological basis unaltered. 

From these considerations it follows that the several 
members of an arithmetical series are incapable of defi- 
nition. Succession in time, and the consciousness of one, 
tico, three, etc., are not complex notions abstracted from 
and after a multitude of intuitions, but simple immediate 
intuitions, differing, as far as numeration is concerned, only 
in the order of their presentation. They are not by any 
act of thought compounded, the latter from the earlier: 



PROLEGOMENA LOGICA. Ill 

they cannot be resolved into any simpler elements of con- 
sciousness, presentative or representative, being themselves 
the a priori conditions of consciousness in general. Hence 
the failure of all attempts to analyze numerical calculation 
as a deductive process. Leibnitz, and subsequently Hegel, 
have endeavored to represent the arithmetical processes as 
operations of pure analysis. Assuming, for example, 12 
and 7 and 5, as given concepts, they show that the first 
may be ultimately analyzed into the same constituent units 
as the two last ; and this is regarded as an explanation of 
the whole process of Addition. They overlook the fact 
that, in that process, 12 is not given, but has to be deter- 
mined by the addition of the two other numbers. Arith- 
metic is not, like Geometry, a science whose definitions 
are genetic and preliminary to its processes. The analysis 
of any number into its constituent units presupposes the 
whole operation w T hich it professes to give rise to. We 
may call, if we please, such an analysis defiyiition ; but we 
must not suppose that it in any degree corresponds to the 
definitions of Geometry, or answers the same purpose in 
the ojjerations of the science. 1 

The above considerations are sufficient for our present 
purpose, which is to determine the psychological basis of 
mathematical judgments, and their consequent special char- 
acter as necessary truths, in a distinct sense from that in 

1 Writers of a very different school from that of Leibnitz or Hegel have 
fallen into a similar error with regard to the nature of arithmetical pro- 
cesses. Mr. Mill, for example, regards the whole science of numbers as 
derived from the common axioms concerning equality, and the definitions 
of the several numbers. Stewart appears to have been of the same 
opinion. On the contrary, the whole essentials of the science must be in 
existence before the so-called definitions can be formed. The applications 
of the calculus as an instrument must not be confounded with its essential 
constituents as a science. 



112 PROLEGOMENA LOGICA. 

which the term is applied to logical or physical principles. 
Mathematical judgments are synthetical, based on the 
universal conditions of our intuitive faculties, and are ne- 
cessary, not, properly speaking, as laws of thought, but 
because thought can only operate in conjunction with mat- 
ter given by intuition, and intuition cannot be emancipated 
from its own subjective conditions. Hence we are com- 
pelled to think of our intuitions under the same laws 
according to which they are invariably realized in con- 
sciousness. Judgments of logical necessity, on the other 
hand, are analytical, and rest on the laws of thought, prop- 
erly so called. Their analytical character is a necessary 
consequence of the constitution of the thinking faculty, 
and is so far from being a proof of the unsoundness or 
frivolity of logical speculations, that it is the strongest 
evidence of their truth and scientific value, and leads to 
most important consequences, both in Logic and in Psy- 
chology. 

The nature of these judgments, as well as of those dis- 
tinguished as metaphysically necessary, will be examined 
in the following chapters. 



CHAPTER V. 

ON THE PSYCHOLOGICAL CHARACTER OF METAPHYSICAL 

NECESSITY. 

A distinction between necessary and contingent matter 
is found, somewhat out of place it is true, but still it is 
found, in most of the older, and, among English writers, in 
most also of the recent treatises on Logic 1 The bounda- 
ries of each, however, are not in the majority of instances 
determined with any approach to accuracy. Among the 
schoolmen, the favorite example of a proposition of the 
highest degree of necessity was omne animal rationale est 
risibile; an example consistent enough with the mediaeval 
state of physical science, but which in the present day will 
scarcely be allowed a higher degree of certainty than 
belongs to any other observed fact in the constitution of 
things. An eminent modern Logician gives as an exam- 
ple of a proposition in necessary matter, "All islands are 
surrounded by water;" an example which is only valid in 

1 Matter in this sense must not be confounded with the modality recog- 
nized by Aristotle, and by most of the modern German Logicians. The 
former is an understood relation between the terms of a proposition, — the 
form of the proposition being in all cases "A is B," — and is supposed to 
be of use in determining the quantity of indefinites. The latter is an ex- 
pressed relation, the form of the necessary proposition being "A must be 
B;" and this is applicable to universal and particular propositions indiffer- 
ently. The admission of the latter is still a point of dispute among emi- 
nent authorities; the admission of the former will be tolerated by no 
Logician who understands the nature of his own science. 

10* 



114 PROLEGOMENA LOGICA. 

so far as the predicate forms part of the notion of the 
subject, and which, therefore, has no other necessity than 
belongs to all analytical judgments, — a necessity derived 
from the form, not from the matter. 1 The distinction 
itself, though altogether out of place when Thought is 
considered merely in its relation to Logic, is, in a psycho- 
logical point of view, of considerable importance. The 
following remarks will, it is hoped, throw some light on its 
true character. 

All analytical judgments are necessary; but they cannot 
properly be said to be in necessary matter. They are all 
ultimately dependent on the Principles of Identity and 
Contradiction, "Every A is A," and "No A is not A:" 2 
principles, the necessity of which arises solely from their 
form, without any relation to this or that matter. That 
every triangle has three sides, arises from a mere analysis 
of the notion of a triangle ; as that every island is sur- 
rounded by water, arises from a mere analysis of the notion 
of an island. This necessity is 'derived solely from the 
laws of formal thinking. 

Of synthetical judgments, every statement of a physical 
fact is in contingent matter; at least if the opposite term 
be used in its highest sense. However rigidly certain 
phenomena may be deduced from the assumption of a 



1 Examples of this kind were indeed indiscriminately admitted by the 
scholastic Logicians, who held any proposition to be in necessary matter 
in which the predicate was part of the essence, or necessarily joined to 
the essence, of the subject. But this classification, though tenable per- 
haps in connection with realist metaphysics, is inconsistent with an accu- 
rate discrimination between the matter and the form of thought. 

2 Kant, Kritik der r. V. p. 133; Troleg., § 2. He derives all analytical 
judgments from the Principle of Contradiction. It would be more accu- 
rate to distinguish this principle from that of Identity, and to derive the 
negative judgments from the former, the affirmative from the latter. 



PROLEGOMENA LOGICA. 115 

general law of nature, the law itself remains nothing more 
than an observed fact, of which we can give no other 
explanation than that it was the will of the Creator to 
constitute things in a certain manner. For example : that 
a body in motion, under certain conditions of projection, 
and attracted by a force varying inversely as the square of 
the distance, will describe an ellipse having the centre of 
attraction in one of the foci, — this is matter of demon- 
stration ; but that the earth is such a body, acted upon by 
forces of this description, is matter of fact, of which we 
can only say that it is so, and that it might have been 
otherwise. The original premise being thus contingent, all 
deductions from it are materially contingent likewise. 

The same is the case with all psychological judgments, 
so far as they merely state the fact that our minds are 
constituted in this or that manner. But there is one re- 
markable difference between this contingency and that 
which is presented by physical phenomena. The laws of 
the latter impose no restraint on my powers of thought : 
relatively to me, they are simply universally observed facts. 
There is, therefore, no impediment to my uniting in a 
judgment any two notions once formed; though the corre- 
sponding objects cannot, consistently with existing laws 
of nature, be united in fact. I may thus conceive a moun- 
tain moving, or a stone floating on the water ; though my 
experience has always presented to me the mountain as 
standing, and the stone as sinking. But as regards Psy- 
chology, the powers of my mind cannot be presented to 
consciousness, but under one determinate manifestation. 
The only variety is found in the objects on which they 
operate. I am thus limited in my power of forming notions 
at all, in all cases where I am, by mental restrictions, pre- 
vented from experiencing the corresponding intuition. I 



116 PROLEGOMENA LOGICA. 

have thus a negative idea only of the nature of an intelli- 
gent being constituted in a different manner from myself; 
though I have no difficulty in supposing that many such 
exist. I can suppose, for instance, that there may exist 
beings whose knowledge of material objects is not gained 
through the medium of bodily senses, or whose under- 
standing has a direct power of intuition ; but to conceive 
such a being is beyond my power ; conception being 
limited to the field of positive intuitions. In another 
point of view, both physical and psychological judgments 
may be called necessary ; as the consequence of certain 
established laws, which laws, however, might have been 
otherwise. In this sense, both might be classified as hypo- 
thetically necessary; 1 in opposition to another class of 
judgments, those relating to human actions, which, as will 
hereafter appear, are, in the fullest sense of the term, con- 
tingent. For logical purposes, however, the former classi- 
fication is preferable. 

On the other hand, mathematical judgments have been 
almost universally regarded as belonging to the province 
of necessary matter. 2 We can suppose the possibility of 
beings existing whose consciousness has no relation to 
space or time at all. We can suppose it possible that some 
change in our mental constitution might present us with 
the intuition of space in more than three dimensions. This 
is no more than to admit the possible existence of intelli- 



1 For this expression see Leibnitz, Theodicee, § 37; Duval- Jouve, Logique, 
p. 78. 

2 Universally among those who have accurately distinguished intelligible 
from sensible magnitude. The objections of Sextus Empiricus in ancient, 
and of Hume in modern times, among skeptics, so far as they have any 
special relation to Geometry, as well as those of M. Comte and Mr. Mill, 
among sensationalists, are mainly based on a confusion of these two. 



PROLEGOMENA LOGICA. 117 

gent creatures otherwise constituted than ourselves, and, 
consequently, incomprehensible by us. But to suppose the 
existence of geometrical figures, or arithmetical numbers, 
such as those with which we are now acquainted, is to 
suppose the existence of space and time as we are now 
conscious of them ; and, therefore, relatively to beings 
whose mental constitution is so far similar to our own. 
Such a supposition, therefore, necessarily carries with it 
all the mathematical relations in which time and space, as 
given to us, are necessarily thought. For mathematical 
judgments strictly relate only to objects of thought, as 
existing in my mind ; not to distinct entities, as existing 
in a certain relation to my mind. They therefore imply 
no other existence but that of a thinking subject, modified 
in a certain manner. Destroy this subject, or change its 
modification, and we cannot say, as in other cases, that the 
object may possibly exist still without the subject, or may 
exist in a new relation to a new subject; for the object 
exists only in and through that particular modification of 
the subject, and on any other supposition is annihilated 
altogether. It is thus impossible to suppose that a triangle 
can, in relation to any intelligence whatever, have its angles 
greater or less than two right angles, or that two and two 
should not be equal to four ; though it is possible to sup- 
pose the existence of beings destitute of the idea of a 
triangle or of the number two. This is necessary matter, 
in the strict sense of the term ; a relation which our minds 
are incapable of reversing, not merely positively, in our 
own acts of thought, but also negatively, by supposing 
others who can do so. 

There is one other science which has frequently been 
supposed to share this necessity with Mathematics. Met- 
aphysics, though, so far as it deals in merely analytical 



118 PROLEGOMENA LOGICA. 

judgments, it has been sufficiently shown by Kant to be 
incapable of leading to any scientific results, is frequently 
regarded as possessing a certain number of synthetical 
axioms, which, under the various names of Principles of 
Necessary Truth, Fundamental Laws of Human Belief, 
and sometimes even (however incorrectly) of Laws of 
Thought, 1 have held a prominent place in various systems 
of philosophy down to the present time. Two of these 
principles may be especially selected for examination, partly 
on account of the importance attached to them by eminent 
writers, and partly on account of their relation to the Forms 
of Thought recognized by Logic. 

1. The Principle of Substance. All objects of percep- 
tion are Qualities which exist in some Subject to which 
they belong. 

2. The Principle of Causality. 2 Whatever begins to 
exist must take place in consequence of some Cause. 

" I perceive," says Reid, " in a billiard-ball, figure, color, 

1 This nomenclature is sanctioned b}' the authority of M. Royer-Collard. 
" Trois lois de la pensee concourent dans la perception. 

1°. L'etendue et l'impene'trabilite ont un sujet auquel elles sont inhe'r- 
entes, et dans lequel elles coexistent. 

2°. Toutes les choses sont placees dans une duree absolue, a laquelle 
elles participent comme si elles etaient une seule et raeme chose. 

3°. Tout ce qui commence a exister a ete produit par une cause." — 
Jouffroy's Reid, vol. iv. p. 447. 

2 Called also the Principle of Sufficient Reason, or of Determining Reason ; 
though these expressions, as Sir William Hamilton has observed, are used 
ambiguously to denote, conjunctly and severally, the two metaphysical or 
real principles : 1°, Why a thing is ; 2°, Why a thing becomes or is pro- 
duced; and, 3°, The logical or ideal principle, Why a thing is known or 
conceived. — Hamilton on Reid, p. 624. Cf. Leibnitz's Fifth Letter to Clarke, 
§ 125, where he states the principle in three forms : " Ce principe est celui 
du besoin d'une raison suffisante, pour qu'une chose existe, qu'un evene- 
ment arrive, qu'une verite ait lieu." For a criticism on the principle as 
thus given, see Herbart, Lelxrbuch zur Einleitung in die Philosophie, § 39. 



PROLEGOMENA LOGICA. 119 

and motion ; but the ball is not figure, nor is it color, nor 
motion, nor all these taken together ; it is something that 
has figure, and color, and motion. This is a dictate of 
nature, and the belief of all mankind." 1 

On the other hand, Bishop Berkeley had labored hard 
to prove that it was much more consonant to nature, and 
to the common sense of mankind, to deny altogether the 
existence of this imperceptible substance, the supposed 
support of perceptible attributes. " I do not argue," he 
says, " against the existence of any one thing that we 
can apprehend, either by sense or reflection. That the 
things I see with mine eyes and touch with my hands do 
exist, really exist, I make not the least question. The only 
thing whose existence we deny, is that which philosophers 
call matter, or corporeal substance. And in doing of this 
there is no damage done to the rest of mankind, who, I 
dare say, will never miss it. The atheist, indeed, will want 
the color of an empty name to support his impiety ; and 
the philosophers may possibly find they have lost a great 
handle for trifling and disputation." 

"It will be urged," he continues, "that thus much at 
least is true, to wit, that we take away all corporeal sub- 
stances. To this my answer is, that if the word substance 
be taken in the vulgar sense, for a combination of sensible 
qualities, such as extension, solidity, weight, and the like — 
this we cannot be accused of taking away. But if it be 
taken in a philosophic sense, for the support of accidents 
or qualities without the mind — then indeed I acknowledge 
that we take it away, if one may be said to take away that 

1 Intellectual Powers, Essay ii. ch. 19. Compare Descartes, Meditatio 
Secunda, who adduces the changes in a piece of wax as an argument to 
show that the thing itself is conceived as something distinct from its sen- 
sible qualities. 



120 PROLEGOMENA LOGICA. 

which never had any existence, not even in the imagina- 
tion." 1 

But after Berkeley came Hume, who applied to the 
phenomena of internal perception the same process of 
reasoning which Berkeley had applied to the external. 
Within myself, he argued, I am conscious only of impres- 
sions and ideas. The substance called Mind is a mere 
fiction, imagined for the support of these, as the substance 
called Matter is imagined for the support of sensible qual- 
ities. 2 In opposition to these skeptical conclusions, Reid 
and his disciples appealed to the authority of certain uni- 
versally acknowledged axioms, distinguished as Principles 
of Common Sense, or Fundamental Laws of Human Belief, 
of which we can give no other account than that such is 
our constitution, and we must think accordingly. One of 
these is the Principle of Substance, mentioned above. 

It is necessary to speak with diffidence on a point dis- 
puted by philosophers of such eminence ; but if there be 
any truth in the psychological distinction between Thought 
and Intuition, noticed in my first chapter, it will appear 
that the Scottish philosophers, in endeavoring to overthrow 
Hume and Berkeley at once, abandoned the only position 
from which an attack might have been successfully made 
on either of them separately. Hume's philosophy is not 
a legitimate development of Berkeley's, unless we allow 
that our consciousness of mind, as well as of matter, is 
representative only. If it be true that neither mental nor 
material substance, as distinguished from the various states 
and attributes of either, is in any manner presented intui- 
tively, the two theories must stand or fall together. And 

1 Principles of Rinnan Knowledge, xxxv., xxxvii. 

2 Treatise of Human Nature, part iv. §§ 5, 6. 



PROLEGOMENA LOGICA. 121 

this point is over and over again conceded by Reid and 
Stewart. 1 

Under this concession, the appeal to a fundamental law 
of belief is insufficient. Such a law can only state the fact, 
that we are by our constitution compelled to believe in a 
certain relation between two given notions : it does not 
explain how either of such notions could have entered 
into the mind in the first instance. But the appeal becomes 
self-contradictory in the hands of any one who admits the 
views of Locke, or of Kant, concerning the limits of the 
understanding. 2 Either a presentative origin must be 
found for the notions of substance and cause, or we must 
admit that, ii* these instances, the act of thought has 
created its own objects. 

We are therefore compelled to ask, Is this asserted 
analogy between our modes of consciousness in relation 

1 For example : " The attributes of individuals is all that we distinctly 
conceive about them. It is true, we conceive a subject to which the attri- 
butes belong; but of this subject, when its attributes are set aside, we 
have but an obscure and relative conception, whether it be body or mind." 
— Reid, Int. Powers, Essay v. chap. 2. "It is not matter, or body, which 
I perceive by my senses; but only extension, figure, color, and certain 
other qualities, which the constitution of my nature leads me to refer to 
something which is extended, figured, and colored. The case is precisely 
similar with respect to mind. We are not immediately conscious of its 
existence, but we are conscious of sensation, thought, and volition ; oper- 
ations which imply the existence of something which feels, thinks, and 
wills." — Stewart, Elements, Introd. part i. 

2 Yet Kant, no less than Reid, allows that we are not immediately 
conscious of mind, but only of its phenomena. In his hands, however, 
the concession is perfectly suicidal, and forms the weak part of the Criti- 
cal Philosophy. The reader who bears this inconsistency in mind, may 
perhaps find an easier solution to some of Kant's Paralogisms and Anti- 
nomies of Pure Reason than could have been given by the author himself. 
On this subject, the admirable remarks of M. Cousin, in his Sixth Lecture 
on Kant, should be consulted. 

11 



122 PROLEGOMENA LOGICA. 

to matter and mind really tenable? Does it not rather 
appear a flat self-contradiction to maintain that I am not 
immediately conscious of myself, but only of my sensations 
or volitions? Who, then, is this I that is conscious; and 
how can I be conscious of such states as mine f In this case 
it would surely be far more accurate to say, not that I am 
conscious of my sensations, but that the sensation is con- 
scious of itself; but, thus worded, the glaring absurdity 
of the theory would carry with it its own refutation. 1 

The one presented substance, the source from which our 
data for thinking on the subject are originally drawn, is 
myself. 2 Whatever may be the variety of the phenomena 



1 Since the publication of the first edition of this work, the author has 
met with the following passage in Jouftroy's Nouveaux Melanges Philoso- 
pJiiques, p. 275, in which the above argument has been anticipated in sub- 
stance, and almost in language: "These singuliere a soutenir que je ne 
saisis pas la cause qui est moi, que je sens ma pensee, ma volonte, ma sen- 
sation, mais que je ne me sens pas pensant, voulant, sentant! Mais d'oii 
saurais-je alors que la pensee, la volonte, la sensation que je sens, sont 
miennes, qu'elles e'manent de moi, et non pas d'une autre cause ? Si ma 
conscience ne saisissait que la pensee, je pourrais bien concevoir que la 
pense'e a une cause; mais rien ne m'apprendrait quelle est cette cause, ni 
si elle est moi ou toute autre. La pensee ne m'apparaitrait done pas comme 
mienne. Ce qui fait qu'elle m'apparait comme mienne, e'est que je la sens 
emaner de moi; et ce qui fait que je la sens e'maner de moi, e'est que je 
sens la cause qui la produit et que je me reconnais dans cette cause." 

2 Thus Descartes observes {Meditatio Tertia) : " Ex iis vero quag in ideis 
rerum corporalium clara et distincta sunt, qucedam ab idea mei ipsius 
videor mutuari potuisse, nempe substantiam, durationem, numerum, et si 
quce alia sunt ejusmodi." This passage perhaps suggested the observa- 
tion of an illustrious French disciple of the Scottish philosophy, who has 
thus supplied a marked deficiency in the system of his masters : " Le 
moi," says M. Royer-Collard, "est la seule unite' qui nous soit donne'e 
immediatement par la nature; nous ne la rencontrons dans aucune des 
choses que nos facultes observent. Mais l'enrendement qui la trouve en 
lui, la met hors de lui par induction, et d'un certain nombre de choses 
coexistantes il cree des unites artificiellcs." — Jouftroy's Beid, vol. iv. p. 



PROLEGOMENA LOGICA. 123 

of consciousness, sensations by this or that organ, volitions, 
thoughts, imaginations, of all we are immediately conscious 
as affections of one and the same self. It is not by any 
after-effort of reflection that I combine together sight and 
hearing, thought and volition, into a factitious unity or 
compounded whole : in each case I am immediately con- 
scious of myself seeing and hearing, willing and thinking. 
This self-personality, like all other simple and immediate 
presentations, is indefinable ; but it is so because it is supe- 
rior to definition. It can be analyzed into no simpler 
elements, for it is itself the simplest of all ; it can be made 
no clearer by description or comparison, for it is revealed 
to us in all the clearness of an original intuition, of which 
description and comparison can furnish only faint and 
partial resemblances. 

The extravagant speculations in which Metaphysicians 
attempted to explain the nature and properties of the 
soul as it is not given in consciousness, furnish no valid 
ground for renouncing all inquiry into its character as it is 
given, as a power, conscious of itself. 1 That there are 
many metaphysical, or, rather, psychological difficulties, 
still unsolved, connected with this view of the subject, 
must be allowed; 2 but, so long as we remain within the 
legitimate field of consciousness, we are not justified in 
abandoning them as insoluble. To this class belongs the 
question of Personal Identity, or the reference of earlier 
and later states of consciousness to the same subject; an 
immediate consciousness being of present objects only. 

3-30. But the French writer to whom this portion of philosophy is most 
indebted is Maine de Biran. 

1 See Cousin, Lecons sur Kant, p. 197; Damiron, Psychologic, 1. i. ch. iv. 

2 See Herbart, Lehrbuch zur Eirileitung in die Philosophic, § 124; Haupt- 
punctc der Metaphysik, §§ 11, 12. 



124 PROLEGOMENA LOGICA. 

The following question may perhaps furnish a hint of the 
data from which the solution of this problem may be 
attempted. Time and Space are given as forms or condi- 
tions of the several phenomena of internal or external 
consciousness ; but are the same conditions strictly appli- 
cable to the conscious subject itself? I may speak, accu- 
rately enough, of my earlier or later thoughts or feelings ; 
but, apart from metaphor, can I, with any philosophical 
accuracy, speak of an earlier or later self, even as a mere 
logical distinction for the purpose of afterwards identifying 
the two ? To identify is to connect together in thought 
objects given under different relations of space or time, as 
when I pronounce the sovereign now lying on my table to 
be numerically one with that which I received yesterday 
at the bank. But is the conscious self ever given under 
these different relations at all? Is it not rather that from 
w T hich our original notion of numerical identity was drawn, 
and which cannot be subjected to later and analogical 
applications of the same idea? 

This one presented substance, myself, is the basis of the 
other notions of substance which are thought representa- 
tively in relation to other phenomena, When I look at 
another man, I do not perceive his consciousness. I see 
only a compound body, of a certain form and color, moving 
in this or that manner. I do not immediately know that 
he perceives, feels, and thinks, as I do myself. He may 
be an exquisitely formed puppet, requiring perhaps more 
mechanical skill in the construction than has ever been 
attained by man, but still a mere machine, a possible piece 
of clockwork. When I attribute to him personality and 
consciousness, I mediately and reflectively transfer to 
another that of which I am directly cognizant only in 
myself. In this case, the phenomena are given in a sen- 



PROLEGOMENA LOGICA. 125 

sible intuition ; the substance is added to them by a repre- 
sentative act of thought. 

Beyond the range of conscious beings, we can have only 
a negative idea of substance. The name is applied in 
relation to certain collections of sensible phenomena, natu- 
ral or artificial, connected with each other in various 
ways : by locomotion, by vegetation, by contributing to a 
common end, by certain positions in space. But here we 
have no positive notion of substance distinct from phe- 
nomena. I do not attribute to the billiard-ball a con- 
sciousness of its own figure, color, and motion; but, in 
denying consciousness, I deny the only form in which 
unity and substance have been presented to me. I have 
therefore no data for thinking one way or the other on 
the question. Some kind of unity between the several 
phenomena may exist, or it may not ; but if it does exist, 
it exists in a manner of which I can form no conception ; 
and if it does not exist, my faculties do not enable me to 
detect its absence. 

Such an acknowledgment of the negative character of 
certain supposed thoughts, i. e., of their not being really 
thoughts at all, is very different from skepticism. It does 
not teach a distrust of our faculties within their proper 
limits, but only tells us that they have limits, and that 
they cannot transgress them. In this there is no more of 
paradox than in asserting that we cannot see a man or a 
tower at a thousand miles' distance. The fault of Berke- 
ley did not consist in doubting the existence of matter, 
but in asserting its non-existence. If I cannot see a sj)°t 
a thousand miles off, I am, as far as sight is concerned, 
equally incompetent to assert that there is or is not a 
tower standing upon it. In like manner, it is character- 
istic of all mere negative notions, that we have no direct 

11* 



126 PROLEGOMENA LOGICA. 

evidence whether their supposed objects exist or not. To 
maintain that matter is a fiction, invented for the support 
of attributes, is to dogmatize in negation, and, after all, to 
give a partial solution only of the question ; for fictions as 
well as facts have their psychological conditions, under 
which alone their invention is possible. 1 Had Berkeley's 
theory been accompanied by an inquiry into the origin of 
negative notions and their influence on thought and lan- 
guage, it could scarcely have given rise either to the 
extreme skepticism of his successor, or to the strange 
misunderstandings of some of his adversaries. 

The conclusion to be drawn from the above remarks is 
sufficiently obvious. The general assertion, that all sensi- 
ble qualities belong to a subject, cannot with any propriety 
be called a principle of necessary truth ; inasmuch as it is 
a principle which may be either true or false, and we have 
no means of determining which. Nor is it correct to call 
it a fundamental law of human belief; if by that expres- 
sion is meant anything more than an assertion of the 
universal tendency of men to liken other things to them- 
selves, and to speak of them under forms of expression 
adapted to such likeness, far beyond the point where the 
parallel fails. The true law or principle which connects 
attributes with a substance extends no further than to the 
phenomena of the personal consciousness, which are neces- 

1 "It seems to be a judgment of nature," says Reicl (I. P. ii. 19), " that 
the things immediately perceived are qualities which must belong to a 
subject; and all the information that our senses give us about this subject 
is, that it is that to which such qualities belong." In point of fact, our 
senses tell us nothing of the kind; and, were these our only intuitive fac- 
ulties, we should never have supposed such a subject to exist. To refer 
any belief to a principle of our nature, is insufficient, unless we can at 
the same time psychologically account for the origin of the notions which 
that belief implies. 



PROLEGOMENA LOGICA. 127 

sarily apprehended as attributes of myself ; and this prin- 
ciple does not warrant us in asserting that the whiteness 
and roundness and hardness of the billiard-ball are attri- 
butes of the ball, in the same manner as my thoughts and 
feelings and sensations are attributes of me. Nevertheless, 
there is a real, though an incomplete analogy between the 
two cases ; which may serve in some degree to account for 
the association which has led to the apparent recognition, 
in the universal language of mankind, of a relation which 
has no warrant in our immediate consciousness. Though 
bodily attributes are not perceived as related to a sub- 
stance, they are in all cases perceived as related to each 
other. The perception by sense of any phenomenon of 
matter is necessarily accompanied by an intellectual appre- 
hension of its relations to space, as occupying it, and con- 
tained in it. Color cannot be perceived without extension, 
nor extension without solidity ; and solidity is not a single 
attribute, but includes in its comprehension the three 
dimensions of length, breadth, and thickness. But we can 
analyze in language what we cannot analyze in conscious- 
ness ; and by the appropriation of distinct names to the 
related attributes we are enabled to speak of them apart, 
though we cannot perceive them except in conjunction. 
This is the real distinction indicated by the use of concrete 
or abstract terms : the round, hard, white body denotes 
the attribute as perceived in space; the roundness and 
hardness and whiteness severally denote the same attri- 
butes as separated in language. This real distinction is 
coupled with an association transferred from the personal 
consciousness ; and men speak of the roundness and hard- 
ness and whiteness of the ball, as they speak of my thoughts 
and my feelings and my desires, without being aware that 
the relation which in the latter case is a fact of conscious- 



128 PROLEGOMENA LOGICA. 

ness, is in the other an imaginary parallel, which cannot 
be positively verified by consciousness, though for the 
same reason it cannot be positively denied. 

But, though there is thus no speculative reason for 
accepting or rejecting Berkeley's theory as true or false, or 
for attempting to adapt to it common forms of speech, 
there may, in certain philosophical inquiries, be a practical 
reason for accepting or rejecting it as convenient or incon- 
venient. If the method of metaphysical research can in 
any degree be simplified by divesting it of the hypothesis 
of a substratum of sensible attributes, this will be a suffi- 
cient reason for accepting the theory as pro tanto valid. 
Such simplification will not, however, be effected by taking 
the Berkeleian theory in its whole extent. The admission 
of ideas as the immediate objects of perception, whether 
in Berkeley's form, as entities distinct from the mind, or in 
Fichte's, as modifications of the mind itself, and the neces- 
sary consequence that nothing exists except when it is 
j>erceived, is too repugnant to the common sense of man- 
kind to have any ultimate value in philosophy. There is 
still room, however, for an attempt to construct a similar 
theory, viewed from the objective side, which, banishing 
the hypothesis of a substratum, shall regard the sensible 
attributes as the things themselves. Whether such a the- 
ory would offer any ground for constructing Metaphysical 
Science on a surer basis, or whether it would share the 
fate of preceding systems, remains to be seen. 1 

Much of the above reasoning is applicable to the Prin- 

1 Something of this sort may perhaps be attempted in connection with 
Sir William Hamilton's doctrine of Natural Realism. But that doctrine, 
admirable as it is in mam - of the fragments that have been published, is 
unfortunately least complete in its ontological relations. On the really 
weak side of Berkeley's Philosophy, see Appendix, note B. 



PROLEGOMENA LOGICA. 129 

ciple of Causality likewise. I hold a piece of wax to the 
fire, and it begins to melt. 1 Here my senses inform me 
only of two successive phenomena: the proximity of the 
fire, and the melting of the wax. That the one is the 
productive cause of the other, is an addition to the sen- 
sible data, which, so far as this particular instance is con- 
cerned, is not given, but inferred. Here, again, it becomes 
necessary to inquire whether we shall abandon the belief in 
Causes altogether; whether we shall concede that Thought 
alone is competent to create the notion ; or whether Ave 
can discover any intuition in which Causality, as distinct 
from mere Succession, is immediately presented. 

Hume, and subsequently Brown, denied altogether the 
existence of Cause in this sense of the term. With these 
philosophers, a cause is nothing more than something prior 
to the change, and constantly conjoined with it. "We 
give the name of cause" says Brown, "to the object which 
we believe to be the invariable antecedent of a particular 
change ; we give the name of effect reciprocally to that 
invariable consequent ; and the relation itself, when con- 
sidered abstractly, we denominate power in the object that 
is the invariable antecedent, — susceptibility in the object 
that exhibits, in its change, the invariable consequent. We 
say of fire, that it has the poioer of melting metals, and of 
metals, that they are susceptible of fusion by fire, — that 
fire is the cause of the fusion, and the fusion the effect of 
the application of fire ; but in all this variety of words 
we mean nothing more than our belief, that when a solid 
metal is subjected for a certain time to the application of 

1 See Locke, Essay, b. ii. ch. 26, who erroneously regards the production 
of change as perceptible by the senses. The other and very different 
origin suggested by the same philosopher (Essay, b. ii. ch. 21) is the germ 
of the theory of Maine de Biran. 



130 PROLEGOMENA LOGICA. 

a strong heat, it will begin afterwards to exist in that dif- 
ferent state which is termed liquidity, — that in all past 
time, in the same circumstances, it would have exhibited 
the same change, — and that it will continue to do so in 
the same circumstances in all future time." 1 

Thus far Hume and Brown are at one. Into the subor- 
dinate question at issue between them, as to the origin of 
our belief in the uniformity of nature, it is foreign to my 
present purpose to enter. I have at present to do only 
with that portion of the theory in which both philosophers 
are agreed, — the resolution of cause into invariable ante- 
cedent ; concerning which Reid remarks, that we may learn 
from it that night is the cause of day, and day the cause 
of night ; for no two things have more constantly followed 
each other since the beginning of the world. 

In the theory of causation, as above stated, two very 
distinct principles are fused into one; and the fusion is 
indicated by the two words invariable antecedent. Admit- 
ting for the moment that causation means no more than 
immediate antecedence in time, it is obviously one thing 
to say that every event must have some antecedent or other, 
and another to say that this particular event must always 
have this particular antecedent. The latter assertion, which 
implies the assumption of the uniformity of nature in her 
operations, is, even granting its universal truth, obviously 
a law of things, and not of thought, the contradictory of 
which is at any time perfectly conceivable. There is no 
absurdity in the supposition, whether it be true or not as 
a fact, that the phenomenon C may at one time be pre- 
ceded by A, and at another by B ; the other circumstances 
being in both cases exactly alike. Whether such a vari- 
ation actually takes place under the existing constitution 

1 Inquiry into the Belation of Cause and Effect, p. 12. 



PROLEGOMENA LOGICA. 131 

of the world which we inhabit, is another question ; but 
there is certainly no difficulty in conceiving that in an 
imaginary world it may take place. This portion of the 
principle being thus excluded from the class of necessary 
truths, the remaining portion will not be difficult to explain. 
The assertion that every event must have some antecedent 
or other, implies no more than that we cannot conceive it 
as standing at the absolute beginning of all time, apart 
from any relation to a preceding series of phenomena. 
This is an obvious result of the subjection of our conscious- 
ness to the law of time. For our consciousness of time is 
not of time in the abstract, but of phenomena as taking 
place in time ; and the law which compels us to conceive 
every event as occurring in time, obviously compels us 
also to conceive it as related to some temporal antecedent. 1 
But, as thus limited, the principle, however necessary, is 
obviously inadequate as a theory of causation. We can- 
not help feeling that there is a deficiency even in the 
original theory as stated by Hume; we feel that cause 
implies something more than invariable antecedent, and 
that Reid's instance of day and night, if it does not amount 
to a philosophical refutation of the theory, is at least a 
practical proof of its insufficiency. The feeling becomes 
still stronger when the element of invariability itself is 
shown to be an adventitious accretion, and the original 
principle is reduced to the mere acknowledgment of a 
temporal antecedent of some kind or other. Rightly or 
wrongly, all men do in fact unite with the idea of temporal 
antecedence that of productive power, and regard this 

1 In thus acknowledging one element of the principle of Causality to 
depend on the mental law of existence in time, I have partially adopted 
the theory of Sir W. Hamilton. For some observations on the remainder 
of that theory, see Appendix, note C. 



132 PROLEGOMENA LOGICA. 

addition as essential to the conception of a Cause. A 
belief so universal, even if it be delusive in a portion of 
its extent, can only be explained, even as a delusion, by 
the supposition that it has an origin in truth ; that there 
is such a notion as power given in the actual facts of 
consciousness, however it may be extended in imagination 
beyond the data which suggested it. 

The philosophers of the school of Reid could not fairly 
meet Hume's theory of causation, for the same reason that 
they could not fairly meet his theory of substance ; because 
they denied the existence of an immediate consciousness 
of mind, as distinguished from its several states. It was 
easy for Hume to show that volition is but one phenom- 
enon, and motion is but another; and that the former is so 
far from being the necessary cause of the other, that a 
stroke of paralysis may put an end even to the uniformity 
of the sequence. It was also easy for him to show that, 
as the motion of the arm is not the immediate consequent 
of the volition, but is separated from it by an intervening 
nervous and muscular action, of which we are unconscious, 
the one cannot be directly given as produced by the other. 
The intuition of Power is not immediately given in the 
action of matter upon matter ; nor yet can it be given in 
the action of matter upon mind, nor in that of mind upon 
matter ; for to this day we are utterly ignorant how mat- 
ter and mind operate upon each other. We know not how 
the material refractions of the eye are connected with the 
mental sensation of seeing, nor how the determination of 
the will operates in bringing about the motion of the 
muscles. We can investigate severally the phenomena of 
matter and of mind, as we can examine severally the consti- 
tution of the earth and the architecture of the heavens : 
we seek the boundary-line of their junction, as the child 



PROLEGOMENA LOGICA. 133 

chases the horizon, only to discover that it flies as we 
pursue it. 

There is thus no alternative, but either to abandon the 
inquiry after an immediate intuition of power, or to seek 
for it in mind as determining its own modifications; 1 a 
course open to those who admit an immediate conscious- 
ness of self, and to them only. My first and only presen- 
tation of power or causality is thus to be found in my 
consciousness of myself as willing. In every act of voli- 
tion I am fully conscious that it is in my power to form 
the resolution or to abstain ; and this constitutes the pre- 
sentative consciousness of free will and of power. Like 
any other simple idea, it cannot be defined ; and hence 
the difficulty of verbally distinguishing causation from 
mere succession. But every man who has been conscious 
of an act of will, has been conscious of power therein ; and 

1 This is clearly and accurately stated by M. Cousin : " Cherche-t-on la 
notion de cause dans Taction de la bille sur la bille, comme on le faisait 
avant Hume, ou de la main sur la bille, et des premiers muscles locomo- 
teurs sur leurs extremites, ou meme dans Taction de la volonte sur le mus- 
cle, comme Ta fait M. de Biran, on ne la trouvera dans aucun de ces cas, 
pas meme dans le dernier, car il est possible qu'il y ait une paralysie des 
muscles qui rende la volonte impuissante sur eux, impi'oductive, incapable 
d'etre cause et par consequent d'en suggerer la notion. Mais ce qu'au- 
cune paralysie ne peut empecher, c'est Taction de la volonte sur elle- 
meme, la production d'une resolution, c'est-a-dire une causation toute 
spirituelle, type primitif de la causalite, dont toutes les actions exterieures, 
a commencer par Teffort musculaire, et a finir par le mouvement de la 
bille sur la bille, ne sont que des symboles plus ou moins infideles." 
— Fragments Philosophiques, Preface de la premiere edition. James Mill 
(Analysis of the Human Mind, vol. ii. p. 256) speaks of the idea of power 
in the relation of cause and effect as "an item altogether imaginary." 
Such a thorough-going imagination is a psychological impossibility: the 
item must be given in one relation before it can be imagined in another. 
No effort of imagination can create its object out of nothing. 

12 



134 PROLEGOMENA LOGICA. 

to one who has not been so conscious, no verbal descrip- 
tion can supply the deficiency. 

Here again, as in the case of substance, as soon as we 
advance beyond the region of consciousness we find our- 
selves in the midst of negative notions, which we can 
neither conceive, nor affirm, nor deny. Our clearest notion 
of efficiency is that of a relation between two objects, 
similar to that which exists between ourselves and our 
volitions. 1 But what relation can exist between the heat 
of fire and the melting of wax, similar to that between a 
conscious mind and its self-determinations ? Or, if there 
is nothing precisely similar, can there be anything in any 
degree analogous ? We cannot say that there is, or, if 
there is, how far the analogy extends, and how and where 
it fails. "We can form no positive conception of a power 
of this kind : we can only say that it is something dif- 
ferent from the only power of which we are intuitively 
conscious. But, on the other hand, we are not warranted 
in denying the existence of anything of the kind ; for 
denial is as much an act of positive thought as affirmation, 
and a negative idea furnishes no data for one or the other. 

The principle of Causality is thus precisely analogous to 
that of Substance, in its origin and legitimate application, 
as well as in its perversion. The idea of power cannot 
legitimately be extended beyond the phenomena of per- 
sonal consciousness in which it is directly manifested. 
But the phenomena of matter are thus far similar to those 
of mind, that both alike are subject to the law of time ; 
the phenomena of nature being in all cases preceded by 
other phenomena, as the phenomena of volition are pre- 
ceded by a productive energy of the person willing. The 
relation which is given in the latter alone is transferred by 

1 See Rcid, Active Powers, Essay i. ch. v. 



PROLEGOMENA LOGICA. 135 

association to the former; and men speak of the power of 
fire to melt wax, as they speak of their own power of self- 
determination, without being aware that, in departing 
from the field of consciousness, they have departed from 
the only province in which the term power has any posi- 
tive significance. 1 What is meant by power in a fire to 
melt wax? How and when is it exerted, and in what 
manner does it come under our cognizance? Supposing 
such power to be suspended by an act of omnipotence, 
the Supreme Being at the same time producing the suc- 
cession of phenomena by the immediate interposition of" 
his own will, — could we in any way detect the change? 
Or suppose the course of nature to be governed by a 
preestablished harmony, which ordained that at a certain 
moment fire and wax should be in the neighborhood of 
each other; that, at the same moment, fire by itself should 
burn, and wax by its own laws should melt, neither affect- 
ing the other, — would not all the perceptible phenomena 
be precisely the same as at present ? These suppositions 
may be extravagant, though they are supported by some 
of the most eminent names in philosophy ; but the mere 
possibility of making them shows that the rival hypothesis 
is not a necessary truth; the various principles being 
opposed, only like the vortices of Descartes and the gravi- 

1 Thus M. Engel observes : " Dans ce que nous appelons force d'attrac- 
tion, d'affinite, ou meme d'impulsion, la seule chose connue (c'est a-dire 
representee a l'imagination et aux sens), c'est l'effet opere, savoir, le rap- 
prochement des deux corps attires et attirant. Aucune langue n'a de mot 
pour exprimer ce je ne sais quoi (effort, tendance, nisus), qui reste absolument 
cache, mais que tous les esprits concoivent neeessairement comme ajoute a 
la representation phenomenale." (See De Biran, Nouvelles Considerations, 
p. 23.) The ce je ne sais quoi expresses exactly the negative character of 
the notion in question. 



136 PROLEGOMENA LOGICA. 

tation of Newton, as more or less plausible methods of 
accounting for the same physical phenomena. 

Before we can positively assert, as a principle of neces- 
sary truth, that all physical phenomena must have a cause, 
we must ascertain clearly what meaning we attach to the 
word cause. If we eliminate the notion of power, which 
has no positive significance in this relation, and confine 
ourselves to that of chronological succession, we may 
assign three different meanings to the term cause, and 
three different degrees of certainty to the corresponding 
principle. If we mean no more than that every event 
must have some chronological antecedent, the principle is 
a necessary truth, dependent upon an original law of the 
human consciousness, by which we are compelled to con- 
template all phenomena as taking place in time. If we 
advance a step beyond this, and add to the notion of 
succession that of invariability, or repetition of similar 
phenomena under similar circumstances, the principle 
may be stated in two different ways. We may inter- 
pret Cause to mean simply invariable antecedent, in which 
case the principle may be expressed as follows: Every 
phenomenon which takes place in nature is preceded by 
some other phenomenon, or aggregate of phenomena, 1 
with which it is invariably conjoined. Or, secondly, re- 
garding the invariability as one of consequence and not 
of antecedence, we may enunciate the principle in a some- 



1 This last limitation is necessary : the cause, to speak accurately, is the 
sum total of the conditions, whose united presence is followed invariably 
by the effect. It is not any single phenomenon, unless we can, by succes- 
sive experiments, eliminate all the concomitants save one, and thus show 
that, as far as the given effect is concerned, they are indifferent. This, 
however, in practice, is seldom the case. On this subject some valuable 
remarks will be found in Mill's Logic, book iii. ch. 5. 



PROLEGOMENA LOGICA. 137 

what more complex form : Every phenomenon which 
takes place has, among its immediate antecedents, some 
one phenomenon or aggregate of phenomena, which being 
repeated, the same consequent j)henonienon will invariably 
recur. 

As-stated in the first of the above forms, the Principle 
of Causality is no more than an induction from experience, 
and can never at highest amount to more than the asser- 
tion of a general fact in nature. We are not warranted in 
stating, prior to observation, that the two phenomena A 
and B are so invariably connected together that nature 
never presents, and man can never produce, a single 
instance of the latter without the precedence of the for- 
mer. Such a conclusion may be established, as a matter of 
fact, by a long course of observation : it may be regarded 
as extremely probable beforehand, from what observation 
teaches us of the uniformity of nature in other instances : 
but in these cases it is not a principle of necessary truth ; 
it is an inductive law or general fact in the constitution of 
nature as now established by the will of God. It is thus, 
and it might be otherwise. 

In point of fact, the principle, as thus explained, is so far 
from being necessary, that it has not yet been ascertained 
to be true. As far as observation has hitherto gone, the 
same phenomenon occurs at different times with totally 
different antecedents. Thus, as Mr. Mill has observed, 
one set of observations or experiments shows that the sun 
is a cause of heat ; another, that friction is a cause of it ; 
others, that percussion, electricity, and chemical action, are 
also causes. It is very possible, indeed highly probable, 
that further observation may hereafter discover some one 
uniform feature running through these several sources; 
but this is only a probability supported by the analogy of 

12* 



138 PROLEGOMENA LOGICA. 

nature in other instances ; it is not a necessary law of our 
own minds compelling us, prior to experience, to pronounce 
that a plurality of jmysical causes is impossible. 

The second form of the principle is less open to excep- 
tion. For, though it may be a matter of question whether 
the same phenomenon may not proceed from a variety of 
physical causes, it appears to be beyond all doubt that any 
one of those causes, whenever it takes place, will be ade- 
quate to the production of the eifect. Thus expressed, 
the law in question is identical with that belief in the 
universal connection of similar events, which Hume re- 
duces to the result of association, which his antagonists of 
the Scottish school refer to an original principle of our 
nature ; while Mr. Mill holds it to be itself an instance of 
induction, and induction by no means of the most obvious 
kind. 

None of these solutions is entirely satisfactory. That 
of Hume has been sufficiently refuted even by the disciple 
of his general theory, Brown; and the refutation holds 
good, whether we suppose, with Brown, that the theory in 
question is a dogmatic position maintained by Hume him- 
self, or whether, with Sir W. Hamilton, we regard it 
merely as the recluctio ad absurdum of the dogmatism 
then in vogue. That of an original principle of our nature, 
though true as far as it goes, is too vague, and confounds 
under one general term things which it should be the 
principal object of any mental classification to distinguish. 
There are some original principles of our nature of immuta- 
ble obligation ; and there are others which are perpetually 
leading us astray. There are some which lead us to truths 
which we cannot reverse even in thought ; and there are 
others which point out only contingent and variable phe- 
nomena. Sight and hearing, appetite and desire, the law 



PROLEGOMENA LOGICA. 139 

of conscience, and the intuitions of space and time, are all 
equally original principles of our nature ; that is, we can 
ultimately give no account of them, but that it has pleased 
our Maker so to constitute us. Mr. Mill's explanation over- 
looks the fact, that when the principle in question is found 
in apparent conflict with experience, it is invariably as- 
sumed to be in the right, and experience in the wrong; 
which is not the case with merely inductive laws : to say 
nothing of the paralogism of making the ground and prin- 
ciple of all induction itself dependent upon induction, and 
upon induction only. Our earliest and unphilosophical 
inductions appear as often to indicate variety in the opera- 
tions of nature as uniformity. The sun rises and sets, the 
tide ebbs and flows, with regularity ; but storm and calm, 
rain and sunshine, appear to observe no fixed order of 
succession. But, in any instance whatever of physical 
causation, let an apparent repetition of the cause not be 
followed by that of the effect, and all men alike, philo- 
sophical or unphilosophical, will at once assert that there 
was some latent variety in the circumstances, and not a 
change in the uniformity of their succession. 

The Principle of Causality, as thus exhibited, seems to 
combine in one formula two separate elements, the one 
necessary, the other empirical. That matter in every rela- 
tion is subject to some law, by virtue of which a given 
antecedent admits at any one time of only one possible 
consequent, seems to be a necessary and unavoidable con- 
viction. That this law will be manifested by the production 
of similar phenomena on similar occasions, is the result of 
a combination of this necessary conviction with the expe- 
rience of the actual evidence of law in our own world, in 
those cases which are most open to observation. I can 
suppose it possible that in another world the law may be 



140 PROLEGOMENA LOGIC A. 

manifested in another way, according to which the phe- 
nomena of matter may have no settled relations to each 
other, but phenomena at one time and in one place con- 
nected, as cause and effect, may at another time or in 
another place have no connection at all. But even in this 
case, I can only conceive the material agents as passively 
obeying the law of their organization, not as enabled, by 
their own caprice, to obey or disobey on different occasions. 
Whether the perceptible results be more or less regular, I 
am still compelled to believe that, in any single instance, 
the antecedent circumstances being given, the consequent 
cannot but be determined by them in one way and in one 
way only ; whether a similar antecedent will on a future 
occasion be followed by a similar consequent or not. 

At the same time I am not entitled to pronounce, a 
priori, that matter cannot possibly disobey its own law; 
though assuredly I am unable to conceive how it can do 
so. And we have thus a remarkable parallel between the 
general law of causation, as applicable to physical phenom- 
ena, and the psychological facts of our own constitution, 
the reverse of which, as was observed at the beginning of 
the present chapter, may be supposed, but cannot be con- 
ceived. And this parallel, I am inclined to think, furnishes 
a key to the true character of the law. If we were told 
of an instance on our own globe in which the repetition 
of exactly similar phenomena had apparently not been 
followed by the same effect, we should without hesitation 
account for it on one of two grounds : either the phenom- 
ena were not really exactly similar, or the interposition 
of some intelligent being had prevented the natural result. 
And if we w T ere asked why these two alternatives alone 
are admissible, we should probably reply, " Because matter 
cannot change of itself." And probably, if we were 



PKOLEGOMENA LOGICA. 141 

informed that in some other world, where the laws of 
matter are manifested otherwise than by regular succes- 
sion, the natural relation had in any given instance not 
taken place, we should ascribe it in like manner to some 
external intervention, not to any power of obedience or 
disobedience residing in the matter itself. Whatever rela- 
tion of cause and effect is conceived as existing between 
two material phenomena, whether limited to a single 
occasion or repeated in orderly recurrence, we find it 
impossible to attribute to the phenomena at that particular 
time anything like self-action, or a choice of alternatives 
to determine or be determined in this way or that. Now, 
why cannot we think of matter as acting by itself? Be- 
cause power and self-determination have never been given 
to us, save in one form, that of the actions of the conscious 
self. What I am to conceive as taking place, I must con- 
ceive as taking place in the only manner of taking place 
in which it has ever been presented to me. This reduces 
the law of Causality, in one sense indeed, to an empirical 
principle, but to an empirical principle of a very peculiar 
character ; one, namely, in which it is psychologically 
impossible that experience should testify in more than one 
way. Such principles, however empirical in their origin, 
are coextensive in their application with the whole domain 
of thought. They cannot, properly speaking, be called 
inductive truths; for they require no accumulation of 
physical experience. The course of Nature is thought as 
uniform, because, so long as Nature alone is spoken of, that 
element is absent which alone we can think of as origin- 
ating a change — Intelligence. And for the same reason, so 
long as the several phenomena of Nature are believed to 
be each under the control of a separate intelligence, the 
axiom of her uniformity will admit of perpetual modifica- 



142 PROLEGOMENA LOGICA. 

tion. The winds may blow north or south, as suits the 
caprices of iEolus ; Xanthus may neglect the laws of his 
periodical rise and fall, to arrest the progress of Achilles ; 
and even the steady-going coachman, Phoebus, may alter 
upon occasion the pace of his chariot, to gratify the wishes 
of his roving parent. 

To call the Principle of Causality, as thus explained, a 
Law of Thought, would be incorrect. We cannot think 
the contrary, not because the laws of thought forbid us, 
but because the material for thought is wanting. Thought 
is subject to two different modes of restriction : firstly, 
from its own laws, by which it is restricted as to its form ; 
and, secondly, from the laws of intuition, by which it is 
restricted as to its matter. The restriction, in the present 
instance, is of the latter kind. "We cannot conceive a 
course of nature without causation, as we cannot conceive 
a being who sees without eyes or hears without ears ; be- 
cause we cannot, under existing circumstances, experience 
the necessary intuition. But such things may, notwith- 
standing, exist ; and, under other circumstances, they might 
become objects of possible conception, the laws of the 
process of conception remaining unaltered. This will be 
more clearly seen hereafter, when we come to treat of 
Logical Necessity and the Laws of Thought. 

The Principle of Causality may thus, as far as its ne- 
cessity is concerned, be referred to an intermediate place 
between the axioms of mathematics and the generaliza- 
tions of physical science, being contingent in some degree 
as compared with the former, and necessary in some degree 
as compared with the latter. It is contingent, inasmuch 
as it relates to circumstances to which our experience is 
subjected in the present state of things, and those circum- 
stances might possibly have been different. It is necessary, 



PROLEGOMENA LOGICA. 143 

inasmuch as, while those circumstances remain as they are, 
the conviction produced by them is unavoidable, in thought 
no less than in fact. The necessity has thus a negative, 
not a positive origin ; and this origin suggests a practical 
caution as regards the employment of the principle. Our 
immediate intuition of power, as has been before observed, 
is to be found in the consciousness of mind as modifying 
itself, the ego determining its own volitions. That mind 
operates upon matter, we are not immediately conscious. 
It is not given in any intuition that the determination of 
the will acts upon the muscles of the arm; though the 
motion of the latter follows the generation of the former. 
Hence, though we are compelled to ascribe all change to 
the only power of which we are conscious, we are unable 
to ascribe it in the only manner of operation of which we 
are conscious. For purposes of scientific investigation, the 
principle is thus purely negative, though it serves to regu- 
late our belief. We know not to this day, and we never 
can know in this life, how mind operates upon matter; 
though we must believe that, in some way or other, it does 
so operate. It is impossible, therefore, to construct de- 
ductively any system of Natural Philosophy from the 
Principle of Causality, or from any other axiom expressing 
the agency of mind upon matter. The value of such prin- 
ciples is purely psychological. 

From the view above given of the Principle of Causality, 
some important consequences might be drawn relatively to 
other sciences ; which, however, my present limits do not 
permit me to attempt. One such remark, however, will, I 
trust, be tolerated, both from the intrinsic importance of 
the question to which it relates, and from its connection 
with the doctrines of an eminent author, 1 to whom I have 

1 For the argument of Mr. Mill, here alluded to, see Appendix, note D. 



144 PROLEGOMENA LOGICA. 

been considerably indebted in the preceding pages. If 
the view above taken be sound, we are enabled to detect 
a fundamental fallacy in the argument in favor of necessity 
from the determination of the will by motives. If every 
thing in nature, it is argued, must have a cause or sufficient 
reason, the determinations of the will cannot be exempted 
from this general law. If I am determined by motives in 
the formation of every act of volition, then there is some- 
thing previous to such act which made it to be necessarily 
produced. If I am not so determined, there is an effect in 
nature without a cause. In this argument, there is a latent 
ambiguity of language. As applied to Physics, the cause 
of a phenomenon is a certain antecedent fact, which being 
repeated, the phenomenon will recur. This notion of cause 
is gathered from material phenomena, and can only by an 
imperfect analogy be applied to mental. In this sense, 
motives addressed to the will are not causes ; for, in every 
act of volition, I am fully conscious that I can at this mo- 
ment act in either of two ways, and that, all the antecedent 
jDhenomena being precisely the same, I may determine one 
way to-day, and another way to-morrow. To speak of the 
determinations of the will as caused by phenomena, in the 
same sense in which the fusion of metal is caused by fire, is 
to give the lie to consciousness for the sake of theory; On 
the other hand, if cause be interpreted to mean an agent 
with power, my only positive notion of cause in this sense 
is derived from the consciousness of myself as determining, 
not as determined. Of the power of motives upon my will, 
consciousness tells me nothing; but only that the one is 
presented and the other follows; not, however, as in Phys- 
ics, uniformly. My notion of causes with power, other 
than myself, is derived from the primary intuition of my- 
self as a cause, and cannot be made to react upon that 



PROLEGOMENA LOGICA. 145 

intuition, without the fallacy of deducing the known from 
the unknown. Of myself, as necessitated by motives, my 
immediate consciousness tells me nothing. It is a mere 
inference from a supposed general law of causality, which 
law is itself derived from the consciousness of the very 
reverse. You are conscious, says the necessitarian, of 
yourself as a determining cause ; therefore you must be a 
determined effect. By what logic does this follow? If 
these considerations suggest a limit to the universality of 
the principle of sufficient reason, so be it. No principle 
can consistently be allowed so much universality as to 
overthrow the intuition from which it had its rise. 1 

Another observation will not be deemed unimportant 
by those who are aware how many philosophical theories 
have been constructed on the sole basis of philosophical 
phraseology. 2 Locke has laid some stress on the fact, that 
the names which stand for insensible actions and notions 
are derived from those of sensible objects. " To imagine, 
apprehend, comprehend, adhere, conceive, instil, disgust, 
disturbance, tranquillity, etc., are all words taken from the 
operations of sensible things, and applied to certain modes 
of thinking. By which we may give some kind of guess 
what kind of notions they were, and whence derived, which 
filled their minds who were the first beginners of lan- 

1 The above cursory remarks are of course not designed as a full exam- 
ination of the problem of necessity, but only as a hint for examining one 
of the arguments advanced in its support. More would be out of place 
here. A few additional observations will be found in the Appendix, note E. 

2 It will scarcely be credited that a philosopher of Hegel's eminence 
should have connected a logical theory of judgment with the fact that 
the German Avord Urtheil etymologically means original part. Such a 
method of philosophizing could hardly have been surpassed by Conradus 
Crambe, or his facetious relative Mr. Swan, Gamester and Punster of the 
City of London. 

13 



146 PROLEGOMENA LOGICA. 

guages ; and how nature, even in the naming of things, 
unawares suggested to men the originals and principles 
of all their knowledge." 1 The fallacy of the theory at- 
tached to this fact by Locke himself, and by Home Tooke, 
has been fully exposed by Dugald Stewart ; but it should 
also have been observed that, in point of fact, the obliga- 
tion is not entirely on one side. While, as regards attri- 
butes and phenomena, the language of mental science has 
mostly been borrowed from that of sensation ; in all that 
relates to the notions of cause or force, as has been well 
remarked by Maine de Biran, the language properly be- 
longing to the mental fact has been transferred by analogy 
to the physical. As the basis of a theory, the fact is of no 
great value ; but its weight, such as it is, should at least 
be acknowledged to bear on both sides of the question. 

Before closing the present remarks it is necessary to 
say a few words in reference to an objection which will 
probably have frequently suggested itself to those conver- 
sant with the literature of the subject. The origin here 
assigned to the principle of causality (and the same may 
in some degree be said of that of substance also) may 
perhaps appear to be of too empirical a character to con- 
sist with the amount of universality assigned to the prin- 
ciple itself; besides being in some respects at variance 
with the opinions of those philosophers to whom the pre- 
ceding pages are mostly indebted. 2 Sir William Hamilton 
has remarked, that, if the conception of active power is 
derived, as Reid asserts, from our voluntary exertions, our 
notion of causality would be of an empirical derivation, 

1 Essay, b. iii. ch. i. § 5. 

2 A point at issue between two eminent French philosophers, to whose 
writings I am under considerable obligations, will be considered in the 
Appendix, note F. 



PROLEGOMENA LOGICA. 14T 

and without the quality of universality and necessity. 1 
Reid himself, in another passage, admits the same thing. 
" The proposition to be proved," he says, " is not a contin- 
gent, but a necessary proposition. It is not that things 
which begin to exist commonly have a cause, or even that 
they always in fact have a cause ; but that they must have 
a cause, and cannot begin to exist without a cause. Prop- 
ositions of this kind, from their nature, are incapable of 
proof by induction. Experience informs us only of what 
is or has been, not of what must be; and the conclusion 
must be of the same nature with the premises." 2 

That experience is the chronological antecedent of all 
our knowledge, even of the most necessary truths, is now 
generally admitted. But a distinction is frequently drawn, 
and has been more than once adverted to in the preceding 
pages, between truths or notions of which experience is 
the source, and those of which it is only the occasion. The 
mind, instead of being compared to a tabula rasa, on which 
experience impresses the whole writing, is likened to a 
seed, which must indeed be planted before it will grow ; 
but contact with the soil is only the occasion which calls 
forth the hidden germ of the plant. Both analogies are 
imperfect ; and both, as regards the present question, tend 
rather to darken than to illustrate. The point may be 
better explained by laying aside, as far as is possible, phys- 
ical imagery altogether, and by examining separately the 
relation to experience of notions or concepts, and of judg- 
ments ; instead of confounding both under the vague 
expression, origin of ideas. 

Every general concept is in one sense empirical; for 
every concept must be formed from an intuition, and every 

1 Beid's Works, p. 604. 

2 Iutell. Powers, Essay vi. ch. 6 (p. 455 of Sir W. Hamilton's edition). 



148 PROLEGOMENA LOGICA. 

intuition is experienced. But there are some intuitions 
which, from our constitution and position in the world, we 
cannot help experiencing; and there are others which, 
according to circumstances, we may experience or not. 
The former will give rise to concepts which, without any- 
great impropriety of language, may be called native, or a 
priori ; being such as, though not coeval with the mind 
itself, will certainly be formed in every man as he grows 
up, and such as it was preordained that every man should 
have. The latter will give rise to concepts which, for a 
like reason, may be called adventitious, or a posteriori ; 
being such as may or may not be formed, according to the 
special experience of this or that individual. To the for- 
mer class belong the notions of time and space, as implied 
in all our intuitions, internal or external: to this class 
belong also the notions of seeing, hearing, and such other 
mental operations as, in some manner or other, are per- 
formed by every man not physically deficient in the requi- 
site organs. Of the same kind are the notions of right and 
wrong, which must necessarily arise in the mind of every 
man who has ever performed an action of which his con- 
science approves or disapproves, — and all men must at 
times do both. The numerous controversies concerning 
the existence of a moral sense may be considerably simpli- 
fied by this consideration. 1 On the other hand, to the 
class of adventitious notions belong those of this or that 
color, sound, etc.; in short, of all simple or complex objects 
of perception which it is possible may have been presented 
to the experience of one man and not to that of another. 

But a necessity of which I am conscious, can, like truth 
and falsehood, exist only in judgments. It may be or- 
dained by the laws of my constitution that I must neces- 

1 See Appendix, note G. 



PROLEGOMENA LOGICA. 149 

sarily form certain notions ; but those notions are not 
therefore thought by me as necessary. The simplest form 
in which necessity can be presented to my consciousness is 
that of a judgment, A must be B. This character belongs 
to all such judgments as by the laws of his constitution a 
man must form, supposing him to be possessed of the con- 
stituent concepts. 

There are certain concepts which, whether native or 
adventitious in their own origin, must, when once gained, 
necessarily be thought in conjunction ; there are others 
which we are at liberty to connect or not, according to 
circumstances. This necessity or contingency of judg- 
ments is generally confounded with necessity or contin- 
gency in the corresponding concepts ; but the fact is, that 
they are not even coextensive in their provinces. There 
may be thousands of men who never heard of a circle or 
its radius : there is not one who, those notions being once 
acquired, can fail to see that all the radii of a circle must 
be equal to each other. 

Necessity in judgments is dependent sometimes on the 
laws of thought, sometimes on the laws of other parts of 
our constitution ; and the term may, in another sense, be 
applied to that character in certain judgments which arises 
from the limitation of our faculties, and from the circum- 
stances in which all men alike are placed. Thus, by the 
laws of thought, every part of any given concept, be its 
origin what it may, must be thought as identical with 
itself; and hence arises the logical necessity of all analyti- 
cal judgments. By the laws of our intuitive faculties, all 
objects of external perception have a certain relation to 
Space, and all objects of internal perception to Time; and 
hence arises the mathematical necessity of geometrical and 
arithmetical judgments. Again, the limitations imposed 

13* 



150 PROLEGOMENA LOGICA. 

on our intuitive faculties restrict us, in the case of certain 
intuitions, to one relation only between them; and hence 
arises the psychological necessity of certain judgments, of 
which we can suppose, but cannot conceive, the contrary. 
The restriction in this case is not properly a law regulating 
acts which we can perform, but a bar separating us from 
acts which we cannot perform. None of these classes of 
judgments can properly be termed empirical; being de- 
pendent, not on experience alone, but on experience in 
conjunction with certain laws and limitations of our mental 
constitution. They are thus, to adopt Shaftesbury's cor- 
rection of Locke, if not innate, at least connatural / the 
constitution of man being such that, being adult or grown 
up, at such or such a time, sooner or later (no matter 
when), they will infallibly, inevitably, necessarily spring 
up in him. These laws and limitations of our constitution 
render necessary the adoption of Leibnitz's addition to the 
sensationalist axiom, 1 "Nihil est in intellectu, quod non 
fuerit in sensu, nisi ipse intellectu s." And even with this 
addition, sense must be understood with extreme latitude, 
for every possible kind of external or internal presentation. 
There is another class of judgments in regard to which 
our experience is restricted by the circumstances in which 

1 Nouveaux Essais, 1. ii. ch. 1. This axiom has been attributed to Aris- 
totle, who, in De Anima, iii. 4, compares the intellect before its actual exer- 
cise to a tablet with nothing actually written upon it (ypa/j./xaTeTov & firj^ev 
virdpxet- evreXexeia yeypay.fj.euov). But Aristotle does not regard the blank 
as filled up by the senses, but by the activity of the intellect itself. A 
nearer approach to the sensational tabula rasa may be found in the doc- 
trine attributed to the Stoics by (Pseudo) Plutarch, Be Plac. Phil. iv. 11: 
Of Stou/coi (paaiW orav yevvT)&rj 6 oLubpcairos, e%et to rjyefxovLKbi/ fxepos tt]S 
$ V XVS> ucnrep x^P T VS evepywv els airoypa<pr}v' els tovto fxiav eKaar-qv t&v 
ivuoiwv euairoypd(perai' irpcoros 8e 6 rris avaypa^prjs rpotros 6 diet, tuv cuadrjae- 
tav. Compare Zeller, Fhilosophie der Griechen, iii. p. 31. 



PROLEGOMENA LOGICA. 151 

we are universally placed. This is the case with the results 
of existing physical laws of the universe, which we can 
perfectly conceive reversed, though within our actual 
experience they never are so. I am fully convinced, for 
example, that, under the existing state of things, a stone 
thrown into the water will sink to the bottom ; but it is 
perfectly conceivable that it might float. Lastly, there is 
a class of judgments which are, in the strictest sense, con- 
tingent ; such as relate to the conduct of a voluntary agent, 
who is subject to no necessary restraint, whatever may be 
his moral obligations. 

The above remarks are not designed as an exact state- 
ment of the theory of any previous philosopher, 1 nor as an 
explanation of language which has been hitherto employed 
in describing a supposed origin of our ideas. They are 
offered only as expressing what I believe to be a more 
exact and accurate account than is conveyed by the physi- 
cal analogies already mentioned, by the vague phraseology 
of source and occasion, or by the obscure notions of poten- 
tial and actual consciousness. They likewise help to dis- 
tinguish, what it is important to keep separate from each 
other, necessity in the acquisition of concepts, and neces- 
sity in their combination in judgments. It is hardly cor- 
rect, for example, to call mathematical notions native, or 
a priori; since it is by no means necessary or universal 
among mankind to form the concept of a circle or a tri- 
angle, still less of an ellipse or a parabola. But the judg- 
ments affirming the properties of these figures are necessary 
in the highest possible degree. On the other hand, the 

1 They approach closely to the view given by Maine de Biran in his 
6th and 7th Answer to the objections of Stapfer; but that philosopher 
has hardly marked with sufficient distinctness the positive and negative 
elements. 



152 PROLEGOMENA LOGICA. 

conception of a cause is necessary in its origin ; all men 
being, in some degree, conscious of the exertion of power 
in their voluntary acts. But the necessity of the principle 
of causality, as a proposition, is of an inferior degree to 
that of mathematical judgments. 

The general results may be summed up as follows : 

1. Judgments necessary in the first degree, or logical 
and mathematical necessity. These are dependent on the 
laws of our mental operations ; and their contradictions 
are neither conceivable nor supposable. 

2. Judgments necessary in the second degree, or psy- 
chological necessity. These are dependent on the restric- 
tions of our mental constitution ; and their contradictories 
are supposable, but not conceivable. To this class belong 
the principles of causality and of substance. 

3. Judgments necessary in the third degree, or physical 
necessity. These are dependent on the laws of the mate- 
rial world ; and their contradictories are both supposable 
and conceivable, but never actually true. 

4. Judgments purely contingent, where either contra- 
dictory may be the true or the false alternative. Such are 
all judgments reducible to no law of causation. 

To this class belong at the present moment many judg- 
ments on physical phenomena ; but here the contingency 
solely arises from our ignorance of the law, and may here- 
after be removed. Thus I am certain that the sun will 
rise to-morrow ; but I am uncertain whether the wind will 
blow from the north or south. But this only means that 
we are acquainted with the laws of the one phenomenon, 
and ignorant of those of the other. The progress of 
science may raise all these judgments to cases of physical 
necessity. But my whole consciousness assures me that my 
own voluntary acts are subject to no invariable law, and 



PROLEGOMENA LOGICA. 153 

that to dream of any amount of future science enabling 
a man to predict these, as he can now predict an eclipse, 
and may hereafter predict a change of weather, is perfectly 
chimerical. These last judgments are, therefore, in the 
strictest sense of the term, contingent ; while those of the 
second and third class, as before observed, may be called 
contingent or necessary, according to the different points 
of view in which they are regarded. 

It only remains to point out the relation of the present 
chapter to Logical Science. Accidentally, it may be ap- 
plied to the correction of a few perversions of the Scholas- 
tic Logic, such as the theory of demonstrative syllogisms ; 
but its essential connection with the Science will be found 
in the different forms of conceptions and judgments. 
Though the notions of substance and of cause are obscure 
and negative only, the processes of conception and judg- 
ment, in their primitive form, proceed upon the tacit 
acknowledgment of the existence of something of the 
kind. In the act of conception, for example, different 
attributes are regarded as forming one whole by relation 
to a common substance. My conception of gold, for ex- 
ample, is that of a yellow, hard, heavy body; but the color 
is perceived by the eye, the hardness is discerned by 
touch, the weight is made known by its pressure as it lies 
in my hand. When I conceive these various attributes as 
forming one thing, the gold is neither the color, nor the 
hardness, nor the weight, but the something to which all 
these qualities belong. Again, having conceived gold as 
yellow, and hard, and heavy, I afterwards discover it to be 
soluble. Here, in forming the judgment, gold is soluble, I 
regard the attributes forming the subject and the predicate 
as coexisting in a common substance ; and this identity of 
substance is expressed by the copula. Our ordinary mod- 



154 PROLEGOMENA LOGICA. 

ifications of thought and speech thus contain certain neg- 
ative elements, the notions attached to which no amount 
of reflection or analysis can render perfectly clear and 
distinct ; though they have been instinctively adopted by 
all mankind, and underlie forms of speech and thought 
which are found among all nations. No language can in 
these respects be constructed upon principles of philosoph- 
ical analysis ; for analysis cannot take place till language 
has arrived at a certain stage of maturity ; and, till that 
period, it must be suffered to grow up with all the imper- 
fections consequent on a hasty generalization from the 
data of personal intuition. The logical character of these 
negative notions will be more fully explained when we 
come to examine the distinction between the matter and 
the form of thought. 

A preliminary examination of the principles of substance 
and causality is also necessary, before we can inquire into 
the character of the logical laws of thought. If it were 
strictly accurate to regard the principle of causality, with 
M. Cousin, 1 as a Principle of the Reason ; — if it were 
true that one term of the judgment, that of change, being 
given, the mind is competent by its own act to add the 
other, and assert " change supposes a cause ; " and that this 
term thus added contains a positive element of thought, 
and not a mere negation of the existence of data for think- 
ing ; — if this were the case, the whole Science of Logic 
would have to be remodelled accordingly. The Reason, 
as distinguished in Kant's sense from the Understanding, 
would become a source of speculative truth ; its principles 
would assume the character of Laws of Thought ; and 
Logic would become, according to M. Cousin's conception, 
the passage from Psychology to Ontology : the process of 

1 Cours de JPhihsopMe, Leipon 19. 



PROLEGOMENA LOGICA. 155 

pure Thinking would conduct us to the science of pure 
Beino:. A Lojnc of the Reason would thus become a 
necessary complement of the Logic of the Understanding; 
and a considerable portion, if not the whole, of the Hegelian 
Dialectic must be incorporated with the Formal Science of 
Kant. To show that such a treatment, instead of being a 
completion, would be a corruption of the Science, — instead 
of making Logic fruitful of truths, would make it prolific 
of chimeras, — instead of attaining knowledge, would aim 
at impossibilities, — has been one of the main objects of 
the preceding inquiry. 



CHAPTER VI. 

ON LOGICAL NECESSITY AND THE LAWS OF THOUGHT. 

The result of the two preceding chapters has been to 
mark off two classes of Necessary Truths, which, though 
dependent, as all such truths must be, upon mental laws 
and limitations, do not, properly speaking, exhibit the 
operation of Laws of Thought, nor come within the prov- 
ince of Logic. We have now to examine the psychological 
character of the laws of pure thinking, and the kind of 
necessity exhibited in consequence by strictly logical pro- 
cesses. The following passage from Mr. Mill's Logic may 
serve to introduce the subject: 

" This maxim (the dictum de omni et nullo), when con- 
sidered as a principle of reasoning, appears united to a 
system of metaphysics once indeed generally received, but 
which for the last two centuries has been considered as 
finally abandoned, though there have not been wanting, in 
our own day, attempts at its revival. So long as what 
were termed TJniversals were regarded as a peculiar kind 
of substances, having an objective existence distinct from 
the individual objects classed under them, the dictum 
de omni conveyed an important meaning; because it 
expressed the intercommunity of nature, which it was 
necessary upon that theory that we should suppose to exist 
between those general substances and the particular sub- 
stances which were subordinated to them. That everything 
predicable of the universal was predicable of the various 



PROLEGOMENA LOGICA. 157 

individuals contained under it, was then no identical 
proposition, but a statement of what was conceived as a 
fundamental law of the universe. The assertion that the 
entire nature and properties of the substantia secunda 
formed part of the properties of each of the individual 
substances called by the same name, — that the proper- 
ties of Man, for example, were properties of all men, — 
was a proposition of real significance when man did not 
mean all men, but something inherent in men, and vastly 
superior to them in dignity. Now, however, when it 
is known that a class, a universal, a genus or species, is 
not an entity per se, but neither more nor less than the 
individual substances themselves which are placed in the 
class, and that there is nothing real in the matter except 
those objects, a common name given to them, and common 
attributes indicated by the name ; what, I should be glad 
to know, do Ave learn by being told that whatever can be 
affirmed of a class may be affirmed of every object con- 
tained in the class? The class is nothing but the objects 
contained in it ; and the dictum de omni merely amounts 
to the identical proposition, that whatever is true of cer- 
tain objects, is true of each of those objects. If all ratioci- 
nation were no more than the application of this maxim 
to particular cases, the syllogism would indeed be, what 
it has so often been declared to be, solemn trifling. The 
dictum de omni is on a par with another truth, which in 
its time was also reckoned of great importance, 'Whatever 
is, is;' and not to be compared in point of significance 
to the cognate aphorism, 'It is impossible for the same 
thing to be and not to be;' since this is, at the lowest, 
equivalent to the logical axiom that contradictory proposi- 
tions cannot both be true. To give any real meaning to 
the dictum de omni^ we must consider it not as an axiom, 

U 



158 PROLEGOMENA LOGICA. 

but as a definition; we must look upon it as intended 
to explain, in a circuitous and paraphrastic manner, the 
meaning of the word class?'' 1 

I quote the above passage from a work of high and in 
many respects of deserved reputation, as a remarkable 
instance of the total misconception of the nature and 
purj:>ose of Logic, arising from that erroneous view to 
which I have before alluded, which regards the Aristo- 
telian and the Baconian Organ on as forming portions of 
the same system, and as subservient to the same end, that 
of physical investigation or the discovery of " fundamental 
laws of the universe." That the deductive method may 
be advantageously applied to purposes of physical inquiry 
is unquestionable; and in this respect Mr. Mill has cer- 
tainly not underrated its value. Any single proposition 
of any syllogism or chain of syllogisms may thus materially 
contain a fact or a law of nature ; but that the funda- 
mental principle on which all reasoning is supposed to 
depend can by any possibility exhibit a law of external 
nature and not a law of mind, is a supposition which, if 
tenable, would make a science of Logic impossible. If 
the dictum de omni were, as Mr. Mill supposes, formed on 
the hypothesis that universals had a distinct existence in 
nature apart from the mind that contemplates them, Logic 
might be entitled to rank with Optics or Astronomy, 
as a science of the laws of this or that order of natural 
phenomena; or it might, perhaps, aspire to the character 
of a general Cosmology, including these and other physical 
sciences as subordinate branches ; but it could not pretend 
to the slightest knowledge of the laws which the mind 
obeys in thinking ; and its principles, as mere generaliza- 
tions from experience, could never attain to more than a 

1 Mill's Logic, vol. i. p. 234. , 



PROLEGOMENA LOGICA. 159 

physical necessity, as the statement of certain facts in the 
existing constitution of the world. 

A science is never ultimately benefited by dissembling 
any conclusion to which its principles appear fairly to 
lead ; still less can it gain by adulterating those principles 
themselves with foreign matter, borrowed from other de- 
partments, in the Tiope of obviating the apprehended 
results. In the case of Logic especially, it may be confi- 
dently asserted that nine-tenths of the confusion and mis- 
understanding which still prevail concerning its nature 
and capabilities, have arisen from ill-judged attempts to 
invest it with an appearance of utility in matters alien to 
its province. 1 Let us therefore look the supposed charge 
fairly in the face, and ask what will be the consequences 
if we admit that the fundamental principles of pure think- 
ing are, as they seem to be, analytical or identical judg- 
ments. Is Logic thereby determined to be false or futile ? 
By no means. A system is futile only when it aims at the 
solution of questions beyond the reach of human faculties : 
and even then, the prosecution of such inquiries is attended 
with an indirect benefit ; inasmuch as it is only after re- 
peated failures that men learn to know the true limits of 
their mental powers, and can profit by the precept ulti- 
mately enjoined by a critical psychology : 

" Tecum habita, et noris, quam sit tibi curta supellex." 

It may indeed be humiliating to learn, what such an 
admission necessarily implies, that the understanding of 
man is not furnished with a power of intuition as well as 

1 Rosenkranz, in his preface to Kant's Logic, speaks severely but truly 
on this point : " So ist denn auch die Logik hundertfach von philosophis- 
chen Stumpern utiliter gemisshandelt worden." 



160 PROLEGOMENA LOGICA. 

of thought; but only in the same way as it is humiliating 
to know that he cannot fly like a bird, nor swim like a fish. 
The restriction is one which the Maker of mankind has 
thought fit to impose upon his creatures ; and, regret it as 
they may, they cannot escape from it. If Logic, indeed, 
supplied us with nothing but identical principles, it would 
by no means follow that the study of it is altogether use- 
less ; but, in point of fact, it does very much more. Viewed 
in connection with Psychology, it points to the important 
fact, that these principles are laws of mind ; and this fact 
alone, applied to the past history and future prospects of 
Philosophy, will give rise to a series of practical rules of 
inestimable value in the direction of the mental powers. 

To prove, then, that Logic is either futile or false, it must 
be shown either that it is impossible for a thinking being 
to attain to a knowledge of the laws by which he thinks, 
and to test thereby the legitimacy of the products of 
thought, or that the laws by which the human mind is 
actually governed are different from those universally as- 
sumed and insisted upon by Logicians. But if, on these 
two points, Logic and Psychology are found to be at one, 
each becomes the strongest possible guarantee of the truth 
and scientific value of the other. The laws which the 
logician has all along assumed as the basis of his system 
are now shown to be the very ones by which, from the 
actual constitution of the human mind, the operations of 
thought are regulated; the conclusions arrived at by a 
critical examination of the mental powers are shown to 
be the same laws of thinking which had before been ac- 
cepted as principles from a critical examination of the 
mental products. Thus, by the united forces of Logic and 
Psychology, we advance a step in the most important of 
all speculative knowledge, the knowledge of ourselves and 






PROLEGOMENA LOGICA. 161 

of our capacities ; and so far is either science from being 
thereby proved futile, that they become the strongest pos- 
sible safeguard against all futile speculations, by pointing 
out clearly the nature of the laws of the pure understand- 
ing, and the exact limits within which they are operative. 
Enough has, I trust, been said to vindicate Logic from 
the charge of frivolity, whatever may be the conclusion 
concerning its principles to which our inquiries finally lead 
us. But, in the eyes of a philosopher, such a vindication is 
wholly unnecessary. The only question worthy of a liberal 
mind, as regards the result of any investigation, is not, Is 
it useful ? but, Is it true ? However fully persuaded we 
may be that every speculative truth has its practical ad- 
vantages, to require a foresight of such advantages before 
entering on the inquiry, is to interpose the most effectual 
bar that can be devised to the progress of any knowledge, 
and the attainment of any benefit. 1 The only tenable po- 

1 This is indeed admitted, and ably maintained, by some of that class of 
writers whose researches are most to the taste of the Utilitarian. I am 
happy to be able to quote the following admirable vindication of the pur- 
suit of truth for its own sake, from a philosopher with whose general prin- 
ciples I am by no means inclined to sympathize : 

" Si la puissance pre'ponderante de notre organisation ne corrigeait, 
meme involontairement, dans Tesprit des savans, ce qu'il y a sous ce rap- 
port d'ineomplet et d'etroit dans la tendance generate de notre epoque, Tin- 
telligence humaine, reduite a ne s'occuper que de recherehes susceptibles 
d'une utilite' pratique immediate, se trouverait par cela seul, comme l'a 
tres-justement remarque' Condorcet, tout-a-fait arrete'e dans ses progres, 
meme a l'egard de ces applications auxquelles on aurait imprudemment 
saerifie les travaux purement spe'eulatifs ; car, les applications les plus im- 
portantes de'rivent constamment de theories forme'es dans une simple inten- 
tion scientifique, et qui souvent ont ete cultivees pendant plusieurs siecles 
sans produire aucun resultat pratique. On en pent citer un exemple 
bien remarquable dans les belles speculations des geometres grecs sur les 
sections coniques, qui, apres une longue suite de generations, ont servi, en 
determinant la renovation de l'astronomie, a conduire finalement Tart de 

14* 



162 PROLEGOMENA LOGICA. 

sition that can be occupied by the assailants of Logic must 
be acquired by showing that men do not, as a matter of 
fact, reason consciously or unconsciously according to its 
rules ; that the thinking process is not governed by laws at 
all ; or that its laws are totally different from those which 
the logician lays down. 

But it is time to examine the question itself which has 
given rise to these observations. Are the Laws of Thought 
in reality identical judgments or not? It may, perhaps, 
appear that the so-called frivolity of such judgments is 
the result of unsuspected causes, having their root in the 
nature of the mind itself; that the very feature which is 
selected as the especial object of contempt and ridicule is 
the strongest evidence of the truth and value of the prin- 
ciples which it characterizes. Supposing, then, that the 
act of thinking is governed by certain laws, what might 
we naturally expect to find as the prominent feature by 
which such laws will be distinguished ? A new truth is in 
its very nature partial : it is new only because it is partial; 
— the discovery of the particular attributes of some par- 
ticular thing or class of things. In a psychological point 
of view, the determination of the laws of thought (be their 



la navigation au degre de perfectionnement qu'il a atteintdans ces derniers 
temps, et auquel il ne serait jamais parvenu sans les travaux si purement 
theoriques d'Archimede et d'Apollonius; tellement que Condorcet a pu 
dire avec raison a cet egard : ' le matelot, qu'une exacte observation de la 
longitude preserve du naufrage, doit la vie a une theorie eoncue, deux 
mille ans auparavant, par des hommes de genie qui avaient en vue de sim- 
ples speculations geometriques.' " — Comte, Cours de Philosophic Positive, 
vol. i. p. 64. 

An English philosopher, who has treated of the same subjects in a very 
different spirit, has expi-essed the same sentiment briefly and well: "It 
may be universally true, that Knowledge is Power; but we have to do 
with it not as Power, but as Knowledge." 



PROLEGOMENA LOGICA. 163 

character as judgments what it may) is as much a new 
truth as any other ; being the discovery of a particular 
fact in the constitution of the human mind. But when we 
consider the same laws logically, in their application to the 
products of thought, how is it possible for any new truth 
to be determined by them? As general laws, they can 
have no special relation to this object of thought rather 
than that ; and it is upon such special relations that the 
discovery of every new property must depend. Material 
knowledge arises from the observation of differences : the 
essential feature of laws of thought must be the abstrac- 
tion from all differences. 1 A necessary law of all thinking, 
which shall at the same time ascertain the definite prop- 
erties of a definite class of things, is a contradiction in 
terms ; for it is optional, and therefore contingent, whether 
we shall apply our thoughts to that particular class of 
things or not. But if all men have been thinking, some 
on this thing, some on that, but all under one code of laws, 
what marvel if, when their attention is called to those 
laws, they should ' recognize them as what they have all 
along virtually acknowledged ? Herein at once lies the 
explanation and the justification of the so-called frivolity 
of principles of this kind. They can determine only the 
general attributes common to all objects of thought as 
such ; and these attributes must constitute the very analyt- 
ical judgments which Logic is so much decried for offering. 
Surely, in the name of common sense and common honesty, 
never was outcry more absurd than that which finds fault 
with a science for accomplishing the very purpose which it 
professes to attempt, and for exhibiting the very features 
which, if its pretensions are well founded, and its method 
sound, it necessarily must exhibit. 

1 Kant, Logik, Einleitung vii. p. 219. Ed. Rozenkranz. 



164: PROLEGOMENA LOGICA. 

It is a remarkable fact in the modern history of philos- 
ophy, as regards identical judgments, that, while English 
philosophers, taking their departure from the principles of 
Locke, have been unsparing in their expressions of scorn 
and censure of them as mere verbal trifling, German philos- 
ophers, taking their departure from the principles of Kant, 
have placed them at the head of all philosophy, as the 
only absolute principles of truth and certainty. Yet Kant, 
as well as Locke, and with far more accuracy of discrim- 
ination, perceived and pointed out the impossibility of 
constructing a system of philosophy upon these judgments 
only. That both extremes are equally in error, — that 
both arise from a crude and one-sided view of a philosophy 
not perhaps in all respects consistent with itself, — and 
that the truth lies between the two, is a natural and obvi- 
ous conclusion. To enter into the extravagances of Fichte 
and Schelling would be foreign to the purposes of the 
present work ; but as regards the disciple of Locke, it 
may be observed, that he has no choice but of two alter- 
natives : either to repudiate the attack of his master on 
frivolous propositions, or to retract his refutation of the 
doctrine of innate ideas. If the principles of thought are 
competent to supply any positive addition to what is given 
in intuition, it follows that the act of thought can in so far 
create its own materials. This brings us back, of necessity, 
to the theory of innate ideas. If, on the other hand, the 
understanding can only modify what is given out of the 
act of thought, it follows that analytical judgments are 
not mere verbal frivolities, but fundamental laws of the 
thinking faculty. 

The Laws of Thought, properly so called, may thus be 
psychologically distinguished from the other elements of 
the process by the answers to the following questions : 






PROLEGOMENA LOGICA. 165 

1. What is the material which must be given prior to any 
act of pure thinking? 2. How is that material modified 
by the act of thought itself? 3. What are the conditions 
by which the understanding is bound in such modification? 
The third question will determine the fundamental laws 
.of the several operations of Conception, Judgment, and 
Reasoning. 

The act of conception consists in regarding certain 
attributes as coexisting in a possible object of intuition. 
It has before been remarked, that when the object of intu- 
ition is actual, i. e., now and here present, an act of thought 
is necessary to distinguish it as such from other objects 
simultaneously presented. This, however, is not pure con- 
ception, but conception in conjunction with intuition. In 
pure conception, the attributes are not presented in them- 
selves, but represented by their signs. Hence the necessity, 
in some form or other, of language ; and hence the object 
of intuition, in an act of pure conception, is not presented 
as actual, but represented as possible. 1 

Two preliminary conditions are thus requisite, prior to 
any act of pure conception. Firstly, attributes must be 
given which, in some combination or other, have been pre- 
sented in a former intuition. For, as thought cannot create 
intuition, attributes which have never been experienced 
are not conceivable: They need not indeed have been 
experienced in their present relation, but in some relation 
or other. Thus, though I have never seen that combina- 
tion of a man's head with a horse's body, which is sup- 
posed to constitute a centaur, yet the notion of such a 
conjunction is perfectly conceivable, because both the 
horse's body and the man's head have been presented in 
other combinations. Secondly, as the attributes are now 

i Cf. Krug, Logik, § 15. 



166 PROLEGOMENA LOGICA. 

given in and through their signs, the import of those signs 
is presupposed to be known. A word which I cannot con- 
nect with some known attribute is, for all purposes of 
thought, like the terms of an unknown tongue. Pure 
thought can neither supply defects in the experience of 
things, nor ignorance of the meaning of words. Informa- 
tion on both these points is therefore presupposed. 

These materials being given, how are they dealt with 
by the act of thought, and what are the laws and limits 
which govern or confine the operation ? By the act of 
conception, the given attributes are combined in a unity 
of representation. Are there, then, any cases in which, 
certain attributes being given, I am compelled to think 
them as representing an object? are there any cases in 
which I am forbidden to do so ? and are there any in 
which, as far as thought is concerned, I am left at liberty 
to do as I please ? Pure conception being concerned with 
possible objects of intuition only, the first and third cases 
merge into one. The actual existence of any object can 
be determined only by its actual presence in this or that 
intuition ; and even then the evidence extends only to its 
present existence now and here, not to its necessary exist- 
ence at any future time when it may become an object of 
thought. As an object of a past intuition, it has then a 
possible and representative existence only. 1 The first law 
of pure thinking applicable to conception is thus indicated 

1 "As not now present in time, an immediate knowledge of the past is im- 
possible. The past is only mediately cognizable in and through a present 
modification relative to and representative of it, as having been. To 
speak of an immediate knowledge of the past involves a contradiction in 
adjecto. For, to know the past immediately, it must be known in itself; 
and to be known in itself, it must be known as now existing. But the past 
is just a negation of the now existent; its very notion, therefore, excludes 
the possibility of its being immediately known." — Sir "W. Hamilton, Beid's 
Works, p. 810. 



PROLEGOMENA LOGICA. 167 

by the negative criterion, that there are certain attributes 
which we cannot think as coexisting in any possible object 
of intuition. This leads us to the well-known Principle 
of Contradiction, 1 the most general form of which is, 
"Nothing can be A and not-A ; " or, " No object can be 
thought under contradictory attributes." But, though 
everything which is contradictory is thus inconceivable, it 
cannot be maintained, on the other hand, that everything 
which is not contradictory is conceivable. 2 

But the Principle of Contradiction, as above enunciated, 
can only be applied in thought coordinately with another 
and a positive principle. If an object cannot be thought 
under contradictory attributes, the impossibility arises 
from its having a definite character of its own, including 
one of the contradictories and excluding the other. The 
universe of conceivable objects embraces both A and not- 
A: it is only when definitely conceived as the one that an 
object cannot be conceived as the other. Every object of 
thought, as such, is thus conceived by limitation and differ- 
ence; as having definite characteristics by which it is 
marked off and distinguished from all others; as being, 
in short, itself \ and nothing else. The indefinite ideas, 
therefore, corresponding to the general terms Thing, Ob- 
ject, Being in general, are not concepts, as containing no 
distinctive attributes ; and the general object denoted by 
such terms is inconceivable. This second Law of Thought 
is expressed by the Principle of Identity, " Every A is A ; " 
or, "Every object of thought is conceived as itself." 3 

1 This law, as Krug has remarked (Logik, § 18), ought rather to he called 
the Pi-inciple of Non-Contradiction. 

2 On conceivability as a test of logical possibility, see Sir W. Hamilton, 
BeioVs Works, p. 377. 

3 Cf. Krug, Logik, § 17, who contemplates the principle from the oppo- 



168 PROLEGOMENA LOGICA. 

But these two Laws of Thought necessarily involve a 
third. The object which I conceive is, by the Law of 
Identity, discerned as being that which it is, and by the 
Law of Contradiction is distinguished from that which it 
is not. But these two correlatives must also be regarded 
as constituting between them the universe of all that is 
conceivable ; for the distinction above made is not between 
two definite objects of thought, but between the object of 
which I think and all those of which I do not think. JVot- 
A implies the exclusion of A only, and of nothing else, 
and thus denotes the universe of all conceivable objects 
with that one exception. This relation, in its more gen- 
eral expression, constitutes a third Law of Thought, the 
Principle of Excluded Middle, 1 "Every possible object is 
either A or not- A." These three Principles, of Contradic- 
tion, Identity, and Excluded Middle, constitute the Laws 
of Pure Thinking, or of Thought as Thought. 

Another limitation must be noticed, which, though per- 
haps not properly an a priori law arising out of the nature 
of thought itself, is at least a universally valid a posteriori 
restriction arising from the practical limits of our intuitive 
powers. Thought can only deal with such attributes as 
have been in some manner presented in intuition. Hence, 
in all cases where intuition is impossible, thought is im- 

site side. He is wrong, however, in deducing from it the principle of 
Contradiction, which is an independent axiom. The two have been con- 
founded or identified by many eminent philosophers; as Leibnitz (Reflex, 
sur Locke), Wolf (Ph. Bat. § 271), Kant (Logik, Einl. vii.), Herbart (Einl. 
in die PMosophie, § 39). Hoffbauer (Logik, § 23) shoAvs that the two prin- 
ciples are independent, and that neither can be deduced from the other 
without a petilio principii. 

1 Principium exclusi medii inter duo contradictoria. For the history of this 
expression, and of the Law denoted by it, see Sir W. Hamilton's Lectures 
on Logic, p. 65. 



PROLEGOMENA LOGICA. 169 

possible likewise. Hence arises a class of practical lim- 
itations of thought based on the limitations of possible 
experience. Some of these are partial and accidental only ; 
as in the case of a blind man, who can have no intuitive 
experience of colors. But one at least is common to all 
men, and, so far, psychologically, if not logically, necessary. 
Though, as far as the laws of thought are concerned, it is 
permitted to unite in an act of conception all attributes 
which are not contradictory of each other, it is impossible 
in practice to go beyond a very limited number. The 
number of attributes in the universe not logically repug- 
nant to each other is infinite; and the mind can therefore 
find no absolute limits to its downward progress in the 
formation of subordinate notions. To arrive at a notion 
which shall comprehend within itself all conceivable com- 
patible attributes, and which shall therefore admit of no 
further possible limitation but that of the individual con- 
ditions of presence in space and time, is an act which, if 
not a priori self-destructive, will at least in practice require 
an infinite grasp of mind and an infinite length of time for 
its accomplishment. 1 

Hence it follows at once that a logical Highest Genus, 
and a logical Lowest Species — i. e., a notion so simple as 
to admit of no further subtraction, and a notion so complex 
as to admit of no further addition — are both inconceivable. 
The meaning of these two terms in Logic must not be 

1 This and the preceding condition are sometimes given as the Laivs of 
Homogeneity and Specification. See Kant, Kritik der r. V. p. 510, ed. Rosen- 
kranz; Krug, Loyik, § 45, b; Fries, Syst. der Logik, §21. I prefer to regard 
them as deductions from a higher law. It may be observed, that those 
logicians who insist on the Law of Homogeneity are not consistent in call- 
ing thing or object a concept (Begriflf). The third law joined with these two, 
that of Logical Affinity, or Continuity, is questionable, both as regards truth 
and value. 

15 



170 PROLEGOMENA LOGICA. 

confounded with that which is applicable to this or that 
branch of material science. The Highest Genus in any 
special science is the general class, comprehending all the 
objects whose properties that science investigates; the dif- 
ferent Lowest Species are the classes at which that special 
investigation terminates. In Geometry, for example, under 
the summum genus of magnitudes in space, we find three 
coordinate injimce species of triangles, the equilateral, the 
isosceles, and the scalene. The geometrical properties of 
the figures are not affected by any further subdivision. 
These three classes are therefore lowest species in Geom- 
etry, but not in Logic. For of geometrical limitations, the 
logician, as such, knows nothing. In a mere relation of 
concepts, the notion of an equilateral triangle whose sides 
are three feet long, is a further subdivision of the notion 
of an equilateral triangle ; and out of this again we may 
form the subordinate notion, " an equilateral triangle 
whose sides are three feet long and divided into inches." 
This process may, as far as Logic is concerned, be contin- 
ued ad infinitum. 

The extreme limits of generalization and specification 
being thus inconceivable, we obtain from these conditions 
two characteristics of all logical concepts, namely, that 
they must have both comprehension and extension. Every 
notion, that is to say, as a condition of its conceivability, 
must contain a plurality of attributes, in consequence of 
which it is capable of subordination to a higher notion ; 
and it must contain a limited number only of attributes, 
in consequence of which lower notions may be subordi- 
nated to it. This canon of conceivability, as we have 
seen, is not invalidated by the supposed highest and lowest 
classes of the logicians, which are limits never arrived at 
in any process of actual thought. Neither is it invalidated 



PROLEGOMENA LOGICA. 171 

by the so-called simple ideas, which, according to the 
doctrine of Descartes and Locke, are the limits beyond 
which analysis is impossible. For a simple idea, like a 
summum genus, is by itself inconceivable. In every intu- 
ition it is presented as part of a complex object ; and it 
can in no act of positive thought be contemplated out of 
that connection. Whiteness and redness, for example, are 
given to us in combination with extension ; motion, with 
a moving body ; pleasure and pain, with a conscious sub- 
ject. We cannot represent to ourselves, as a possible 
object of intuition, a color unextended, 1 a motion without 
a moving body, a feeling without a mind. Simple ideas 
are thus never conceived as such, but only forming parts 
of a complex object. That they are indefinable (in Locke's 
view of definition), has been remarked in a former chap- 
ter; but this arises, not from their forming absolutely 
simple concepts, but from their being simple portions of a 
complex intuition. 

From these two characteristics of all concepts follows 
their capability of Definition and Division — the former 
being an enumeration of the higher notions contained in 
the comprehension of a given concept; the latter, an 
enumeration of the lower notions contained in its exten- 
sion. The manner, however, in which these two operations 
are commonly treated in logical writings manifests an utter 
confusion between the general laws of thinking as appli- 
cable to any matter, such as they are laid down in pure 
Logic, and the performance of a special act of thought 
about this or that matter, which forms a portion of this or 
that branch of applied Logic. The so-called Logical Laws 

1 The error of those philosophers who suppose that color can he con- 
ceived apart from extension, has been noticed by Sir W. Hamilton, Betel's 
Works, p. 800. 



172 PROLEGOMENA LOGICA. 

of Definition and Division are merely derived from an 
analysis of the notions of the operations themselves; — 
notions such as might be borrowed concerning any object 
from the art or science to which it materially belongs. In 
the given notion of Definition, as the enumeration of the 
parts comprehended in a concept, it is of course implied 
that it must be adequate, otherwise the parts are not 
enumerated ; and that it is clear, otherwise they are not 
parts. And so of Division, substituting parts of exten- 
sion for those of comprehension. Such an analysis fur- 
nishes no test even of the formal validity of any single 
act of division or definition ; it only takes to pieces the 
general notion of the process. But it is obvious that any 
given notion, borrowed from any source whatever, may be 
analyzed in like manner by an application of thought. 
From the notion of weighing a pound of cheese, it follows 
of course, firstly, that the whole quantity weighed must 
be exactly a pound ; secondly, that any part of the same 
must be less than a pound ; thirdly, that the same ounce 
must not be weighed twice over. If this criterion be 
adopted, a chapter on cheese-weighing has as good a right 
to be placed in Logic, as a chapter on Division or Defini- 
tion. 

The question necessary to determine the true logical 
character of these processes is not, "Given the general 
notions of the two operations, to determine by analysis 
what those notions imply ; " but, " Given any particular 
concept, how much can be ascertained by pure thinking 
concerning its relation to higher or lower concepts ? " 
Viewed in this light, Definition, as a logical operation, is a 
portion of the act of Conception, governed by the same 
laws, and subject to the same limitations. We can deter- 
mine thereby nothing concerning the actual possession of 



PROLEGOMENA LOGICA. 173 

certain attributes by certain objects : we cannot even 
ascertain that objects of any kind really exist in nature. 
Conception being limited to possible objects of intuition 
only, Definition is confined to the analysis and separate 
exposition of the attributes contained in a given concept, 
and determines not their reality but their conceivability. 
Its only logical laws are the Principles of Identity and 
Contradiction : the one compelling us to regard any given 
concept as identical with the sum of its constituent parts, 
and the other pronouncing that a definition which enu- 
merates attributes directly or by implication incompatible 
with each other is logically self-destructive. If the attri- 
butes are compatible, the definition is allowed as valid, as 
far as Logic is qualified to pronounce judgment : for further 
examination it must be referred to the tribunal of ex- 
perience. The purpose of logical definition is thus not 
material accuracy, but formal distinctness as regards the 
intension or comprehension 1 of the concept. 

It is obvious that the rules of definition commonly given 
in logical treatises have no value or significance except in 
extralogical applications. To say that a definition must 
be adequate to the notion which I entertain^ is only to say 
that what I assign as the contents of a notion must be 
what I think to be the contents ; which is, of course, im- 
plied in the fact of my assigning them. The rule acquires 
a material significance when interpreted to mean that the 
attributes assigned in the definition must exactly corre- 
spond to the characteristic features of the object as it exists 
in nature. But, then, to determine whether this rule is 
complied with or not is clearly beyond the province of the 

1 See Drobisch, Neue Darstellung der Logik, § 102. That analytical dis- 
tinctness alone falls within the province of Logic is shown by Kant, Logik, 
Einl. viii. 



174 PROLEGOMENA LOGICA. 

logician. I may assign " rational animal," as an analysis of 
my notion of man ; but to ascertain, as a matter of fact, 
that all men possess reason, and that all other animals are 
without it, is manifestly a question not of thought, but of 
experience. There is no alternative between exempting 
the logician as such from all material knowledge whatever, 
and requiring from him a minute acquaintance with every 
possible branch of human knowledge. If he is bound to 
know, as a matter of fact, that men are rational and horses 
hinnible, he is by the same rule bound to be conversant 
with the constitution and properties of every object which 
nature can present or art produce. 

It is obvious also that Logic can admit one kind of de- 
finition, and one only. The so-called nominal definition 
by synonym or etymology would require of the logician a 
material knowledge of the vocabulary and construction of 
any given language, thus making Logic a compendium 
of all dictionaries and all grammars. 1 The so-called acci- 
dental definition is a logical absurdity. If the notion 
homo, for example, is composed of the notions animal 
rationale, it cannot at the same time contain the distinct 
attributes of bipes implume. To use the same word for 
both combinations is simply to employ language equivo- 

1 " In this place," says Archbishop Whately, " we are concerned with 
nominal definitions only, because all that is requisite for the purposes of 
reasoning (which is the proper province of Logic) is, that a term shall not 
be used in different senses : a real definition of anything belongs to the sci- 
ence or system which is employed about that thing." In the sense in 
which nominal and real definition were distinguished by the scholastic lo- 
gicians, the exact reverse is the truth. Logic is concerned with real, i. e., 
with notional definitions only : to explain the meaning of particular words 
belongs to the dictionaries or grammars of particular languages. But this 
is only one out of thousands of errors committed by various writers, 
through confounding the thing or notion in the mind with the things or in- 
dividuals out of it. Even Kant (Logik, § 106) has not quite avoided this 
ambiguity. 



PROLEGOMENA LOGICA. 175 

cally. It may so happen that all the individuals possessed 
of reason are also provided with two legs and destitute of 
feathers ; but this is not implied in the notion of ration- 
ality, and cannot be elicited by any act of pure thinking. 
For this reason those logicians are clearly right who con- 
sider the enumeration of properties or accidents, not as a 
definition of notions, but as a description of individuals. 
But such a description has clearly no connection with 
Logic, but solely with the natural history of the object 
described. 

Division, on the other hand, corresponds in one sense to 
the remaining portion of the act of Conception, the union 
of the attributes in a possible object of intuition, and is 
thus regulated by the same laws as Definition. But Divi- 
sion, in this sense of the term, is not Specification, but 
Individualization; and moreover pays no attention to 
any coordinate members of the same class, but is solely 
occupied with the one object conceived. It thus belongs, 
not to symbolical, but to intuitive cognition ; being not 
the mere enumeration of the constituent elements of a 
concept, but the verification of their conceivability by the 
aid of the imagination. Such an imagination is in one 
sense a Division ; for it is impossible for me to imagine an 
individual triangle which shall be neither equilateral, isos- 
celes, nor scalene : one of these attributes therefore enters 
into every actual intuition of a triangle, and thus far limits 
and divides the general notion. But, then, the attributes 
added are not in this case contemplated as the constituents 
of a lower class, but of a possible individual. In like man- 
ner, I cannot imagine a man of no color and no stature ; 
but in adding these particulars to my conception, I do not 
think of them as related to any coordinate class, as consti- 
tuting a division of men into tall and short, or white and 



176 PROLEGOMENA LOGICA. 

not white. I think of them only as necessary to test the 
conceivability of the generic attributes with which they 
are combined. The office of Division in this respect is to 
make our conceptions clear, as that of Definition is to make 
them distinct. 1 

Beyond this, the process of Division, as contributing to 
distinctness in the extension of a Concept, cannot be re- 
garded as an act of pure thinking, 2 or as solely determined 
by logical laws. Even in the case of dichotomy by contra- 
diction, the principle of division must be given, as an 
addition to the attributes comprehended in the concept, 
before the logician can take a single step. For Division 
is not, like Definition, a mental analysis of given materials: 
the specific difference must be added to the given attri- 
butes of the genus ; and to gain this additional material, 
it is necessary to go out of the act of thought, to seek for 
new empirical data. "Divide animal" is a command 
which no logician, as such, can obey; for the mere notion 
animal does not of itself suggest rational or irrational, 
any more than mortal or immortal, virtuous or vicious, or 
any other attributes not logically incompatible with the 
genus. 3 The principle of division must be given in addi- 
tion to the concept to be divided ; and when it is given, 
the process, thus raised from a material to a formal one, 

1 A conception is clear when its object, as a whole, can be distinguished 
from any other; it is distinct when its several constituent parts can be dis- 
tinguished from each other. The merit of first pointing out these charac- 
teristics of the logical perfection of thought belongs to Leibnitz. See his 
Meditationes de Cognitione Veritate et Ideis. 

2 By pure thinking is not meant thinking which has no relation to any past 
experience; for without some experience, all thought is impossible. It 
means only that we can proceed to the act of thought without additional 
data being required prior to and out of the act itself. The relation of ex- 
perience to thought is too often lost sight of in the Kantian philosophy. 

3 See Fries, System der Loyik, § 92. 



PROLEGOMENA LOGICA. 177 

has, like definition, a potential only, not an actual value in 
relation to experience. If the differentia rational is given, 
I can divide animal into rational and not-rational ; but if 
the differentia mortal is given, I can also, as far as Logic 
is concerned, divide into mortal and immortal. I must 
appeal to experience, and not to thought, to determine 
whether one or the other of these divisions is actually true ; 
whether the Struldbrugs of Luggnagg or the Undying 
Fish of Bowscale Tarn are really existing animals or not. 
Every concept is potentially divisible by any two given 
differentia?, contradictory of each other, and both compati- 
ble with the genus. And the laws by which the process 
is governed are, firstly, the Principle of Contradiction; 
and, secondly, that of Excluded Middle. By the first, we 
are forbidden to think that two contradictory attributes 
can both be present in the same object ; by the second, we 
are forbidden to think that both can be absent. The first 
tells us that both different! m must be compatible with the 
genus : I cannot, for example, divide animal into animate 
and inanimate. The second tells us that one or the other 
must be found in every member of the genus; but in what 
manner this is actually carried out, whether by every ex- 
isting member possessing one of the differentiae and none 
the other, or by some possessing one and some the other, 
experience alone can determine. 1 

It thus appears that even dichotomy by contradiction is 
not, strictly speaking, a formal process, as Kant considers 
it ; 2 but that it is partly material, and so far extralogical ; 
and that the material element predominates still more, 
according as any other principle of division is adopted. 
Where the specific differences are not contradictory, so 

1 Trendelenburg, Logische Untersuchungen, i. 4. 

2 Logik, §113. See, on the other side, Hoffbauer, Logik, §§ 134, 138. 



178 PROLEGOMENA LOGICA. 

that each naturally suggests the other, every one of them 
must be given, prior to any possible act of formal thinking. 
The only division of a concept which can be regarded as 
a purely logical process is that sometimes distinguished as 
Determination, which consists in the reunion of attributes 
previously separated by definition. 1 In a formal point of 
view, therefore, the arrangement of those logicians who 
treat of Definition before Division is preferable to the 
inverse order adopted by Aldrich, Divisionem excipit 
Definitio. 

Throughout the preceding remarks, the presence of all 
the antecedent conditions requisite to the logical perfec- 
tion of cognitions is presupposed. It is taken for granted 
that we are, prior to any act of conception, in possession 
of the materials necessary to complete clearness and dis- 
tinctness, and that the act of thought consists merely in 
eliciting the concept with these qualities out of the suffi- 
cient data. And this supposition is the only one which 
can be admitted into a system of pure Logic, or into 
Psychology in its purely logical relation. The failure of 
materials for conception is precisely analogous to the fail- 
ure of materials for reasoning. In the latter case, if a 
single premise only is given, or two premises so related 
that no necessary conclusion follows from them, the logician 
is not called upon to remedy the deficiency ; he simply 
decides that the data are insufficient for reasoning at all 
In like manner, if the empirical data for clear or distinct 
conception are wanting, the logician, as such, can only say 
that the materials for the thought are insufficient. The 
distinction between clear and obscure, distinct and indis- 
tinct conceptions, is as much out of the province of pure 
Logic, as a distinction between syllogisms whose premises 

i See Drobisch, §§ 17, 29, 30. 



PROLEGOMENA LOGICA. 179 

necessitate their conclusion, and reasonings in which the 
consequence may with more or less probability be conjec- 
tured. In conception and in judgment, as well as in 
reasoning, there are processes necessitated by the laws of 
thought from certain data ; there are others which are not 
necessitated, but which maybe hazarded with more or less 
risk of error ; the presumption in their favor amounting in 
some cases to a moral certainty, and binding upon our 
practice, but never reaching the height of logical necessity 
or speculative perfection. 1 The first class alone are recog- 
nized by Pure Logic, and that in relation not merely to 
reasoning, but to all three operations of thought. Applied 
Logic, in the Kantian sense of the term, may treat of the 
several practical imperfections of human thought, which 
lower in this or that special instance the logical standard 
of perfection. Here we may treat of notions more or less 
obscure or confused, of judgments more or less uncertain, 
of reasonings more or less inconsequent. The object of 
the present observations is rather to ascertain what light 
may be thrown by psychological considerations on the 
purely logical processes, and to call attention to the fact, 
that the distinction between material and formal thinking 
may and ought to be consistently carried out in reference 
to all the operations of the understanding. 

Judgment is distinguished from Conception by the dif- 
ference of its data. In Conception, attributes are given, 
to be united by thought in a possible object of intuition ; 
in Judgment, concepts are given, to be united by thought 
in a common object. Like Conception, also, Judgment may 
be considered either as pure, or as combined with a present 
intuition. Pure judgments are those in which the given 
concepts are of such a character that their mutual relation 

1 Cf. Ki*ug, Logik, § 35, Anm. 1. 



180 PROLEGOMENA LOGICA. 

of agreement or difference can be determined by an act of 
thought alone, without any appeal to experience. This is 
the case when the attributes comprehended in the one con- 
cept form either the whole or a part of those comprehended 
in the other ; or where some attribute comprehended in the 
one is contradictory of one of those comprehended in the 
other. In the former case we are enabled at once, by the 
law of Identity, to unite the two concepts in an affirmative 
judgment, and in the latter, by the law of Contradiction, 
to separate them by a negative judgment. But this class 
of judgments (being those commonly known as analytical 
or explicative) may, with more propriety, be included un- 
der the head of Conception. The affirmative analytical 
judgment is in fact nothing more than the Definition, com- 
plete or partial, of the subject-notion; while the negative 
judgment expresses only the necessary condition of all 
conception, which, by discerning any notion as being that 
which it is, necessarily excludes it from all that it is not. 

In synthetical or ampliative judgments, the act of 
thought is not sufficient to determine the relation of the 
concepts to each other, without the accompaniment of an 
intuition, pure or empirical. For example : in order to 
form the judgment, "Two straight lines cannot inclose a 
space," I must not only be able to conceive separately the 
two notions of a straight line and of an inclosing of space, 
but I must also, by the aid of imagination, construct a 
representation in my mind of two actual straight lines and 
their actual positions in space. I must perceive that these 
two straight lines are incapable of inclosing a space, before 
I pronounce the universal judgment concerning all pairs 
of straight lines. Here the relation between the two con- 
cepts is presented in a pure or a priori intuition, i. e., in 
an intuition containing no adventitious element external 



PROLEGOMENA LOGICA. 181 

to the mind itself. Again, in order to form the judgment, 
"Gold is heavy," supposing that my conception of gold 
does not in itself include the attribute of weight, I cannot, 
by merely thinking of gold as a hard, yellow, shining body, 
determine what effect it will produce when laid on the 
hand. I must actually place an individual piece of gold 
on my hand, and ascertain by experience the fact of its 
pressure. Here the relation between the two concepts is 
presented in a mixed or empirical intuition, i. e., in an 
intuition caused by the presence of a body external to the 
mind itself. 

Yet in this class of judgments, as well as in the former, 
when the necessary intuition has once been given, the act 
of thought itself is governed by the same laws of Identity 
and Contradiction. In pronouncing that two distinct 
notions are united in one and the same object, that it is 
the gold which is heavy, I unite the concepts "gold" and 
" heavy " in a complex notion comprehending both, and 
denoting the union of both in a common object. That 
which was before conceived as "gold," is now conceived 
as " heavy gold " (whether the new attribute becomes part 
of the meaning of the term gold or not is of no conse- 
quence), and this complex notion is now exhibited in the 
act of judgment, as analyzed into its constituent parts, and 
identified with them. 1 Synthetical judgments may thus, 
as far as the mere act of thought is concerned, be brought 
under the same law as analytical ones, namely, the Prin- 
ciple of Identity when the judgment is affirmative, and 
that of Contradiction when it is negative. 

Another law of thought is sometimes given as the 
foundation of Judgment, under the name of the Logical 
Principle of Sufficient Reason. This law, which must be 

1 Sec Drobiscli, Neue Darstdlung der Logik, § 35. 
16 



182 PROLEGOMENA LOGICA. 

carefully distinguished from the Metaphysical Principle 
of Causality, is enunciated, " Every judgment must have 
a sufficient ground for its assertion." x But, in truth, the 
relation of this principle to the act of judgment is merely 
negative : it forbids us in certain cases to judge at all, and 
it does no more. If the judgment is analytical, the law of 
Identity or of Contradiction is the sufficient reason for 
making it. If the judgment is synthetical, we have, pre- 
viously to the given intuition, no reason at all; and, accord- 
ingly, we suspend our thought till we have referred the 
decision to the tribunal of experience. The only logical 
reason for a thought of any kind is its relation to some 
other thought ; and this relation will in each case be de- 
termined by its own j>roper law. The Principle of Suffi- 
cient Reason is therefore no law of thought, but only the 
statement that every act of thought must be governed by 
some law or other. 2 



1 See Kant, Logik, Einleitung vii. ; Fries, Syst. der Logik, § 41 ; Krug, 
Logifc, § 20; Thomson, Laws of Thought, p. 296. 

2 In excluding the Principle of Sufficient Reason from the laws of 
thought I am happy to find myself supported by the authority of Sir 
William Hamilton in the philosophical Appendix to his Discussions, pub- 
lished subsequently to the first edition of the present work. " The Princi- 
ple of Sufficient Reason" he says, " should be excluded from Logic. For, 
inasmuch as this principle is not material (material = non-formal) it is 
only a derivation of the three formal laws; and inasmuch as it is ma- 
terial, it coincides with the principle of Causality, and is extralogical." 
Kant {Logik, Einleitung vii.) takes a different view. He regards the Princi- 
ple of Contradiction as the criterion of the logical possibility of a judg- 
ment, that of Sufficient Reason as the criterion of its logical reality. But 
of judgments, as distinguished from the conclusions of syllogisms, the 
only logical reality is possibility. Directly I have ascertained two notions 
not to be contradictory to each other, I have made an actual judgment of 
the logical possibility of their coexistence; and to take any step beyond 
this, experience is required, and not logic. The difference between prob- 
lematical and assertorial judgments is extralogical. and denends on the 



PROLEGOMENA LOGICA. 183 

Hypothetical and Disjunctive Judgments must be re- 
served for a separate examination. At present, we must 
proceed to investigate the laws of Reasoning. This pro- 
cess differs from Judgment, as Judgment differs from 
Conception, in the nature of its preliminary data. In 
Judgment, concepts are given, thought being required to 
determine their possible coexistence in an object. In Rea- 
soning, one or more judgments are given, thought being 
required to determine what further judgments may be 
elicited from them. Under this head will thus be included 
not merely the ordinary Syllogism, but likewise (so far as 
they contain processes of thought at all) the immediate 
inferences of Opposition and Conversion. In all these, 
the material given prior to the act of thought is a judg- 
ment ; and the process of judging from concepts is thus 
not included, but presupposed; the conclusion being 
always a different judgment, either in form, as regards 
Quantity, Quality, or Relation, which is the case in imme- 
diate consequences; or partially in matter, which is the 
case in mediate reasoning by syllogism. 1 The common 
arrangement, therefore, which places immediate inference 
in the second part of Logic, is objectionable. 2 

question whether a logical judgment is or is not determined by experience 
to be materially true. 

1 See Kant, Logik, § 44. His theory of contraposition affecting the 
modality of the judgment is untenable, and seems to result merely from 
that excessive love of system which must bring in four forms somehow. 
The supposed demonstrative character of the conclusion in contraposition 
is merely a necessity of consequence from the position of the premise; a 
character which is found in all logical reasoning whatever. 

2 This order, however, has by no means been uniformly adopted by Lo- 
gicians. Aristotle treats of Opposition in the De Inter pretatione, and of 
Conversion in the Prior Analytics. Wolf separates Opposition and Con- 
version, considered as relations between two given propositions, from the 
processes of inference derivable from each. The former is treated in con- 



184 PROLEGOMENA LOGICA. 

Opposition may be treated in two points of view. 
Firstly, as a relation between two given propositions ; 
secondly, as a process of inference, in which, one proposi- 
tion being given, another may be determined. In the for- 
mer character, it is merely an explanation of the meaning 
of certain logical terms ; in the latter, it is a process of 
reasoning, a deduction of one proposition as conclusion 
from another as premise, and governed, as we shall see, by 
the same laws as the mediate inference. 1 The primary 
processes, on which the rest may be made to depend, are 
those of Subaltern and Contradictory Opposition ; the 
former being grounded on the Principle of Identity, and 
the latter on those of Contradiction and Excluded Middle. 
Thus in the proposition, "All A is some B," an identity is 
stated between the whole of the objects thought under 
the concept A, and a portion of those thought under B. 2 



nection with Judgment; the latter, under the name of Immediate Conse- 
quence, in connection with reasoning. Kant and his followers treat im- 
mediate consequences as reasonings, under the name of Syllogisms of the 
Understanding ; an arrangement which is logically correct, whatever may- 
be the psychological objections to the nomenclature. 

1 On account of this identity of law, various attempts have been made 
by ingenious writers to reduce immediate consequence to the mediate form. 
Thus Wolf exhibits subaltern opposition as a syllogism with the minor 
premise, " Some A is A;" thus perversely representing the law of thought, 
which governs the reasoning process in general, as a part of the special 
matter given preliminary to a particular act. Still more absurd is the 
elaborate system which Krug, after a hint from Wolf, has constructed, in 
which all immediate inferences appear as hypothetical syllogisms; a ma- 
jor premise being supplied in the form, " If all A is B, some A is B." 
The author appears to have forgotten that either this premise is an addi- 
tional empirical truth, in which case the immediate reasoning is not a logi- 
cal process at all, or it is a formal inference, presupposing the very reason- 
ing to which it is prefixed, and thus begging the whole question. 

2 Throughout the following pages, in order to exhibit the law of 
thought more clearly in each case, I have, in conformity with the views of 



PROLEGOMENA LOGICA. 185 

The conclusion, " Therefore some A is some B," proceeds 
on the principle that every part of A must be identical 
with a part of that which has been given as identical with 
all A. This process resembles the inference in an affirma- 
tive syllogism, except that in the latter there is given a 
double identity ; firstly, of the middle term with a part of 
the major ; and secondly, of the minor with a part of the 
middle. The inferences of Contradictory Opposition are 
based on the Principles of Contradiction and Excluded 
Middle. By the former, when one of two contradictory 
judgments is given as true, we infer that the other is false ; 
and by the latter, when one is given as false, we infer that 
the other is true. The remaining inferences of Opposition 
may be reduced to combinations of the above. 

The several processes of Conversion, if the predicate is 
quantified as well as the subject, may be reduced to Sim- 
ple Conversion only ; and even under the old system, 
Conversion per accidens may be regarded as a combination 
of Simple Conversion with one of the inferences of Oppo- 
sition. 1 Simple Conversion is thus the only one which it 
is necessary to examine. This cannot properly be regarded 

Sir William Hamilton, stated the quantity of the predicate as well as of 
the subject in each proposition. Of the value of this addition to the ordi- 
nary logical forms, I have elsewhere expressed my opinion (North British 
Meview, No. 29). I have not, therefore, thought it necessary to enter into 
an elaborate examination of it here ; especially as it is sufficient for my 
purpose to bring forward only those forms of reasoning universally ad- 
mitted by logicians. In quantifying the predicate in these instances, we 
only express what every treatise on Logic tells us to understand, viz., 
that the predicate of an affirmative proposition is not distributed; i. e., is 
thought as particular. 

1 Thus Aldrich analyzes conversion per accidens. " Sit vera E : Ergo et 
ejus simpliciter conversa: Ergo et conversse subalternata : quae est ex- 
positae conversa per accidens. Sit vera A: Ergo et ejus subalternata: 
Ergo et subalternatse simpliciter conversa : quas est expositse per accidens." 

16* 



186 PROLEGOMENA LOGICA. 

as a process of judgment; for either the converted prop- 
osition is a new judgment distinct from the original one, 
or it is merely the same judgment expressed in different 
language. In the former case, it is an inference from a 
premise, and consequently a process of reasoning; in the 
latter, there is no process of thinking at all, but merely a 
change in the language by which a given thought is ex- 
pressed. The former is the preferable view, so long as the 
subject and predicate of a proposition are viewed in the 
relation of whole and part, whether by the inclusion of 
the subject under the extension of the predicate, or of the 
predicate in the comprehension of the subject. For the 
inversion of the relations of whole and part is sufficient to 
constitute a new judgment. But in the system of Sir W. 
Hamilton, in which every proposition is reduced to an 
equation, or rather to an identification of object between 
the two terms, the latter view seems more accurate ; it 
being manifestly the same thing to identify the object 
thought under A with that of B, and that thought under 
B with that of A. 

To opposition and conversion must be added a third 
process, that of the immediate consequence of one equi- 
pollent proposition from another. 1 The equipollence in 
some cases can only be determined materially ; and the 
consequence is then extralogical ; as in the instance cited 
by Wolf, Titius est pater Caii^ergo Cains est filius Titii; 
but there are other instances in which the consequence is 
formal, and determined solely by the laws of thought. 
Thus, by the principle of contradiction, from the premise, 

1 See Wolf, Philosophic/, Rationalis, § 445; Fries, System der Logik, § 47. 
The former has not accurately distinguished the material from the formal 
cases of this consequence; and it was, probably, this confusion that led 
Kant to reject the inference altogether. 



PROLEGOMENA LOGICA. 187 

All A is B, follows the immediate inference, No A is not- 
B, in which is produced a change of quality from affirm- 
ative to negative. In this way, when one predicate is 
affirmed of a subject, its contradictory may always be 
denied. The process commonly called Conversion by Con- 
traposition, is properly the simple conversion of this equi- 
pollent proposition. 1 

The whole of the preceding observations clearly point 
out the view in which Logic and Psychology must coincide 
concerning the nature and principles of the Syllogism. 
The former, as the science of the laws of pure thinking, 
has nothing to do with the inferences of more or less 
probability furnished by the analogies of this or that branch 
of physical science, nor even with the general constitution 
of the material world, so far as it is known to us only 
empirically as a fact. Its only province is with those infer- 
ences which are necessitated by the laws of thought; 
which, certain data being furnished, we cannot but draw 
as consequences. That the premises of a syllogism neces- 
sarily imply and contain the conclusion, is so far from 
being an imperfection in Logic, that it is a necessary con- 
sequence of the supposition that thought is governed by 
laws at all. And in accordance with this conclusion, Psy- 
chology teaches us that thought is representative and 
reflective, not presentative and intuitive ; that, having no 
positive operation beyond the field of possible experience, 
its laws can only be analytical, and its processes must lead 
not to the acquisition of new knowledge, but to the mod- 
ification of the old. It only remains to exemplify -this 
result by applying it to the ordinary forms of the logical 
syllogism. 

1 This has been remarked by Fries (§ 49, e.), and recently by Mr. Kars- 
lake (Aids to the Study of Logic, p. 65). 



188 



PROLEGOMENA LOGICA. 



Fig. 1. 



All M is some P. 
All S is some M. 
All S is some P. 



No M is any P. 
All S is some M. 
No S is any P. 



Fig. 3. 
All M is some P. 
All M is some S. 
.-. Some S is some P. 



Fig. 2. 
No P is any M. 
All S is some M. 
No S is any P. 



No M is any P. 
All M is some S. 
Some S is not any P. 



The above examples will suffice as specimens of the dif- 
ferent forms of affirmative and negative reasoning admitted 
by the three Aristotelian figures. The fourth figure might 
be easily subjected to the same treatment; but it is pref- 
erable to regard its moods as inverted forms of the first. 
On inspection of these specimens, it appears, that the 
Principle of Identity is immediately applicable to affirm- 
ative moods in any figure, and the Principle of Contradic- 
tion to negatives. In Barbara, for example, the minor 
term all S is identical with a part of M, and consequently 
with a part of that which is given as identical with all 
M, namely, some P. In Darapti, the minor term some S 
is identical with all M, and consequently with some P. 
The principle immediately applicable to both is the axiom, 
that what is given as identical with the whole or a part 
of any concept, must be identical with the whole or a part 
of that which is identical with the same concept. This 
may be briefly expressed by the Principle of Identity, 
Every A is A. In Celarent, Cesare, and Felapton, some or 
all S, being given as identical with all or some M, is dis- 
tinct from every part of that which is distinct from all M. 1 

1 Under the system of a quantified predicate, the second figure admits 
of affirmative syllogisms, which, like the rest, may he referred to the 
principle of Identity. 



PROLEGOMENA LOGICA. 189 

This is briefly expressed by the Principle of Contradiction, 
No A is not-A. 

These two laws govern all the moods of Categorical 
Syllogism, including under them, as subordinate rules, the 
dictum de omni et nullo, or the nearly equivalent axiom, 
nota notce est nota rei ipsius / as well as the distinct ax- 
ioms which have been framed by different logicians as 
rules of the second and third figures. 1 The process of 
Reduction, which is properly and necessarily adopted by 
those logicians who, with Aristotle and Kant, acknowledge 
the principle of the first figure only, now becomes unneces- 
sary and inconsistent ; inasmuch as all the syllogistic fig- 
ures are exhibited as equally direct exemplifications of the 
same general law. For the same reason, the distinction 
adopted by Kant between Syllogisms of the Understanding 
and Syllogisms of the Reason, in addition to the psycho- 
logical impropriety of distinguishing two faculties of 
thought, 2 is now shown to be logically untenable also; 
the processes of immediate and mediate reasoning being 
exhibited as cognate acts of thought, governed by the 
same general laws, and differing only in their material 
data. 

By bearing in mind what has been above said of the 
nature of thought and its laws, we shall also be enabled to 
take a juster view of a process more or less misrepresented 
in the majority of logical treatises, Induction. Scarcely 
any logician has accurately distinguished between Formal 
Induction^ in which the given premises necessitate the 

1 As by Lambert, Neues Organon, part i. h 232; Kant, Logik, § 71; Sir 
"W. Hamilton in Mr. Thomson's Laws of Thought, p. 248, where they are 
given correctly as special applications of a more general principle. 

2 On this question, see Sir W. Hamilton, Discussions, p. 17; Cousin, 
Lecons sur la Philosophic de Kant, p. 168; Krug, Logik, § 74. 



190 PROLEGOMENA LOGICA. 

conclusion in conformity with the laws of thought, and 
Material Induction, in which the conclusion may be in- 
ferred with more or less probability from additional data 
not furnished by the premises; between what we must 
know as thinkers, and what we may know as investigators 
of nature. By some logicians, Induction is treated as a 
Syllogism in Barbara, with the major or minor premise 
suppressed; the advocates of this view overlooking the 
fact, that the suppression of either premise leaves a defi- 
ciency to be supplied independently of the act of thought, 
and thus reduces the whole process from formal to mate- 
rial ; to say nothing of the inversion of the reasoning as 
actually performed, and the destruction of all foundation 
for the syllogistic process from universals to particulars, by 
making every universal premise itself a deduction from a 
higher one. By others, Induction is represented, accord- 
ing to the Baconian view, as an interrogation of nature, 
by the selection, in any physical investigation, of such 
phenomena as may indicate the existence of a general law. 
Here it is forgotten that the fact that nature proceeds by 
uniform laws at all is a truth altogether distinct from the 
laws of thought, and, if not of wholly empirical origin, at 
least one which cannot be ascertained a priori by the pure 
understanding. Others again, struck by the physical diffi- 
culty of an exhaustive enumeration of individual cases, 
endeavor to effect a compromise between material proba- 
bility and formal necessity, by describing the instances 
cited as representatives or samples of their class ; as if the 
nature of samples and representatives could be made 
known by an innate principle of the mind, independently 
of experience. Even the wonderful acuteness of Kant in 
all questions between matter and form appears to have 
deserted him here ; and by describing Induction as a Syl- 



PROLEGOMENA LOGICA. 191 

logism of the judgment, furnishing a logical presumption 
of a general conclusion, he not only encumbers the science 
with an extralogical process, but neglects altogether the 
really formal reasoning which it is the duty of the logician 
to take into account. 1 

The truth is that there are two totally distinct processes 
confounded under the general name of Induction. The 
Baconian or Material Induction proceeds on the assump- 
tion of general laws in the relations of physical phenomena, 
and endeavors, by select observations and experiments, to 
detect the law in any particular case. This, whatever be 
its value as a general method of physical investigation, has 
no place in Formal Logic. The Aristotelian or Formal 
Induction proceeds on the assumption of general laws of 
thought, and inquires into the instances in which, by such 
laws, we are necessitated to reason from an accumulation 
of particular instances to a general or partial rule. The 
process in this case may be affirmative or negative ; and it 
is governed, like other formal reasonings, by the general 
laws of Identity and Contradiction. Specimens of its 
several forms may be exhibited as follows : 

Affirmative Induction. 
X, Y, Z, are some B. X, Y, Z, are some B. 

X, Y, Z, are all A. X, Y, Z, are some A. 

.*. All A is some B. .'. Some A is some B. 



Negative Induction 
X, Y, Z, are not any B. 
X, Y, Z, are all A. 
/. No A is any B. 



X, Y, Z, are not any B. 
X, Y, Z, are some A. 
.'. Some A is not any B. 



Other moods may be added to these, by varying the 
quantity of the predicate in the major premise. By assign - 

1 Two distinguished exceptions to this general error must however be 
noticed. Aristotle's account of Induction, in Anal. Pr. ii. 23, incomplete as 



192 PROLEGOMENA LOGICA. 

ing, in conformity with the system of Sir W. Hamilton, a 
definite quantity to the predicate in all affirmative propo- 
sitions, we are enabled to avoid that ambiguity of the 
copula which has hitherto been the main defect in the 
logical analysis of inductive reasoning. 1 The relation of 
whole and part between the terms of the proposition being 
thus dispensed with, the subject is no longer represented 
as at one time contained under, at another constituting its 
predicate ; but each term, in every case, is equated, or iden- 
tified as to its object, with the whole or a part of the other. 
Under this system it is no longer necessary to distin- 
guish Induction from the third figure of Syllogism, as this 
figure, with a definite predicate, will admit of universal as 
well as particular conclusions. Indeed, every Syllogism in 
this figure, in which the minor premise is collective, may 
be regarded as a logical Induction. In this point of view 
it is manifestly governed by the same laws as the syllogism, 
the affirmative moods by the Principle of Identity, and 
the negative by the Principle of Contradiction. The so- 
called imperfect Induction is altogether extralogical. The 
constituted whole can in thought be identified only with 
the sum total of its parts, not with a few representatives ; 
and without such identification no inference can be neces- 
sitated by the laws of thought. The physical difficulty of 
adducing all the members of a given class is a purely mate- 
rial consideration, like that of the truth of the premises in 
a syllogism, and is assumed, not investigated, by the logi- 
cian. But without such a preliminary datum, we have no 

it is in many respects, has the merit of adhering accurately to the formal 
view of the process. And the admirable Article on Logic by Sir W. Ham- 
ilton, in No. 115 of the Edinburgh Review (reprinted in his Discussions), 
exhibits for the first time the logical character of Induction, divested of 
its material incumbrances and formal perversions. 
1 See Sir W. Hamilton, Discussions, p. 1G3. 



PROLEGOMENA LOGICA. 193 

materials for drawing a universal conclusion by logical 
Induction. 

Thus far we have shown the several forms of mediate 
categorical reasoning to depend on two necessary laws of 
thought, the Principles of Identity and Contradiction. A 
separate examination is needed to ascertain the character 
of the Hypothetical Propositions and Syllogisms, which, 
as I am inclined to think, has not hitherto been accurately 
exhibited, even by the best logicians of the formal school. 

By Kant and his followers, the Hypothetical Proposition 
is described as representing a form of judgment essentially 
distinct from the Categorical ; the latter being thoroughly 
assertorial, the former problematical in its constituent 
parts, assertorial only as regards the relation between 
them. Two judgments, each in itself false, may thus be 
hypothetically combined into a single truth ; and this com- 
bination cannot be reduced into categorical form. 1 The 
Hypothetical Syllogism, in like manner, is a form of rea- 
soning distinct from the Categorical, and not reducible to 
it, being based on a different law of thought, namely, the 
logical Principle of Sufficient Reason, a ratione ad rationa- 
tum, a negatione rationati ad ?iegationem rationis valet 
consequential 

Of this principle, as applied to judgments, I have before 
remarked, that it is not a law of thought, but only a state- 
ment of the necessity of some law or other. As applied 
to syllogisms, it has the same character. It states the 
fact, that whenever a condition, whether material cause 
of a fact or formal reason of a conclusion, exists, the con- 
ditioned fact or conclusion exists also. Thus viewed, it 



1 See Kant, Logik, § 25; Krug, Logik, § 57; Fries, System der Logik, § 32. 

2 Kant, § 76; Krug, § 82; Fries, § 58. 

17 



194 PROLEGOMENA LOGICA. 

is not the law of any distinct reasoning process, but a 
statement of the conditions in which laws of nature or 
of thought are operative. When a material cause exists, 
its material effect follows, and the phenomenon indicates 
a law of nature ; when a logical premise is given, its 
logical conclusion follows, and the result indicates a law 
of thought. What law, must in each case be determined 
by the particular features of the phenomenon or reasoning 
in question ; but a statement of this kind is distinguished 
from laws of thought, properly so called, by the fact, that 
it cannot be expressed in a symbolical form: we require 
the introduction of a definite notion, Cause, Reason, 
Condition, or something of the kind, which is a special 
object of thought, not the general representative of all 
objects whatever. The principle in question is thus only 
a statement of the peculiar character of certain matters 
about which we may think, and not a law of the form of 
thought in general. 

It is obvious that the relation of premises and conclusion 
in a syllogism may, like any other relation of condition 
and conditioned, be expressed in the form of a hypotheti- 
cal proposition : " If all A is B, and all C is A, then all 
C is B;" and the actual assertion of the truth of these 
premises will furnish at once a so-called hypothetical syllo- 
gism : "But all A is B, and all C is A, therefore all C 
is B." This was observed by Fries, who hence rightly 
maintains that analytical hypothetical judgments are for- 
mal syllogisms. 1 It is strange that, after this, he should 
not have gone a step further, and discovered that syn- 
thetical hypothetical judgments are assertions of material 
consequences. The judgment, " If A is B, C is D," asserts 
the existence of a consequence necessitated by laws other 

1 System der Logik, § 44. 



PROLEGOMENA LOGICA. 195 

than those of thought, and consequently out of the prov- 
ince of Logic. The addition of a minor premise and con- 
clusion in the so-called hypothetical syllogism, is merely 
the assertion that this general material consequence is 
verified in a particular case. 

The distinction so much insisted on by the Kantians, 
of the problematical character of the two members of a 
hypothetical judgment, is, like the whole Kantian doctrine 
of modality, of no consequence in formal Logic. All 
formal thinking is, as regards the material character of 
its objects, problematical only. Formal Conception pro- 
nounces that certain objects of thought may possibly exist, 
leaving their actual existence to be determined by expe- 
rience. Formal Judgment decides on the possible coex- 
istence of certain concepts ; and Formal Reasoning, on 
the truth of a conclusion, subject to the hypothesis of the 
truth of its premises. 

To state that this hypothesis is in a certain instance 
true, adds nothing to the logical part of the reasoning, but 
only verifies the empirical preliminaries which the logician 
in every case assumes as given. To exhibit a formal 
consequence hypothetically, is only a needless reassertion 
of the existence of data which the act of thought presup- 
poses. To exhibit a material consequence hypothetically, 
is not to make it formal, but only to assert that, in a 
certain given instance, a consequence not cognizable by 
Logic takes place. The sequence of " C is D," from " A 
is B," is not one whit more logical than it was before ; it 
is only stated to take place materially in the present case. 

The omission of hypothetical syllogisms has frequently 
been deemed a defect in Aristotle's Organon ; and his 
French translator takes some fruitless pains to strain his 
text, in order to make out that he does in fact treat of 



196 PROLEGOMENA LOGICA. 

them. 1 If there is any truth in the preceding observa- 
tions, it will follow, that Aristotle understood the limits 
of Logic better than his critics ; and that his translator 
had better have allowed the omission as a merit than have 
attempted to deny it as a fault. When the hypothetical 
proposition states a formal consequence, the reasoning 
grounded upon it may always be reduced to categorical. 
When it states a material consequence, it states what the 
logician, as such, cannot take into account. Aristotle is 
therefore quite right in saying, that in this case the con- 
clusion is not proved, but conceded? Syllogism may be 
employed as a logical proof of the antecedent : the conse- 
quent is admitted to follow on grounds which the logician, 
as such, does not investigate, but which maybe warranted 
by the principles of this or that material science. 

The true character of hypothetical reasoning is lost 
sight of in the examples commonly selected by logicians, 
which have for their subject a proper name, and indicate, 
not a general relation of reason and consequent between 
two notions, but certain accidental circumstances in the 
history of an individual. The adoption of this type has 
led to the logical anomaly, that the propositions of a 
hypothetical syllogism are generally stated without any 
designate quantity ; whereas it is obvious that, wherever 
concepts are compared together in any form of reasoning, 
two distinct conclusions may follow, according to the 
quantity assigned. For example, to the premise, " If men 
are wise, they will consult their permanent interests," we 
may supply two minors and conclusions, in the construc- 
tive form, according as we affirm the antecedent of all 
men or of some. It thus becomes necessary to distinguish 

1 St. Hilairc, Logique d'Aristote Traduite en Francois, Preface, p. lx. 

2 Anal. Prior, i. 23, 11. 



PROLEGOMENA LOGICA. 197 

between two different kinds of apparently hypothetical 
syllogisms, — those in which the inference is from a gen- 
eral hypothesis to all or some of its special instances, and 
those in which a relation between two individual facts is 
assumed as a hypothesis leading to a singular conclusion. 
The former contain a general relation of determining and 
determined notion, which may always be expressed in 
three terms ; the occasional employment of four being 
only an accidental variety of language. Thus the general 
assertion, "If any country is justly governed, the people 
are happy," is equivalent to, "If any country is justly 
governed, it has happy people." This we may apply to 
special instances ; all countries, some countries, or this 
country, being asserted to be justly governed: and this 
is properly hypothetical reasoning. The latter denote 
only a material connection between two single facts, either 
of which may, to certain minds possessed of certain addi- 
tional knowledge, be an indication of the other; but the 
true ground of the inference is contained in this additional 
knowledge, and not in the mere hypothetical coupling 
of the facts by a conjunction. This is not hypothetical 
reasoning ; i. e., it is not reasoning from the hypothesis, but 
from other circumstances not mentioned in the hypothesis 
at all. 1 

1 This may be made clearer by an example. The following is cited by 
Fries as an instance of a hypothetical proposition not reducible to cate- 
gorical form : " If Caius is free from business, he is writing poetry." 
This may be interpreted to mean either, generally, " Whenever Caius is 
disengaged, he writes poetry; " or, specially, " If he is now disengaged, he 
is now writing poetry." Under the former interpretation, it is a general 
hypothesis, which may be applied as a major premise to particular in- 
stances; but in this case the true form of the reasoning is, "All times 
when Caius is disengaged are times when he writes poetry; and the pres-. 
ent is such a time." Under the latter interpretation, it is one of the cases 

17* 



198 PROLEGOMENA LOGIC A. 

It thus appears that the only hypothetical judgment 
which can be employed as the real major premise of a 
syllogism may be expressed, in the form, " If A is B, it is 
C," where A, B, and C, represent concepts, or general 
notions. The complete categorical equivalent to this is, 
" Every A which is B is C, because it is B," which admits 
of two interpretations, according as B stands for the 
physical cause of the fact, or for the logical reason of our 
knowing it. In the latter case, the judgment is analytical, 
and represents a disguised formal consequence, with B as 
a middle term ; e. g., " Every man who is learned has 
studied, because he is learned." Here the notion of study 
is implied in that of learning, and the major premise is, "All 
learned beings have studied." The hypothetical proposi- 
tion thus becomes a complete syllogism, to which the sub- 
sequent consequence is related as an episyllogism. 1 In the 
former case, where B stands for a physical cause, the judg- 
ment is synthetical, and indicates a material consequence, 
which it requires some additional knowledge of facts to 

of a material connection of two facts mentioned in the text. Now, in 
this last case, it is obvious that the inference is really made, not from the 
hypothesis, but from some circumstance known to the reasoner, but not 
appearing in the proposition. Any man being asked, " Why do you infer 
that Caius, being now disengaged, is writing poetry?" would reply, "Be- 
cause he told me he should do so; " or something of the kind. Assuredly 
he would never dream of replying, " Because if he is now disengaged he 
is writing." In this case, then, he does not reason from the hypothesis, and 
the expressed propositions do not compose a syllogism. 
iThus: 



Hypothetical Syllogism. 
If any man is learned, he has 

studied : 
Some men are learned ; 
.•. Some men have studied. 



Categorical Analysis. 
All learned beings have studied : 
All learned men are learned be- 
ings; 
All learned men have studied : 
Some men are learned men; 
Some men have studied. 



PROLEGOMENA LOGICA. 



199 



reduce to formal; e. g., " All wax exposed to the fire melts, 
because it is exposed." Plere, on material grounds, we 
know that we cannot supply the premise, " All bodies 
exposed to the fire melt;" but only, "All bodies soluble 
by heat and exposed to the fire melt." In this case the 
consequence is extralogical, and requires additional data 
not given in the thought. But nere, also, when the judg- 
ment in question is employed as the premise of a rea- 
soning, the conclusion follows categorically ; though the 
premise itself cannot, as it stands, be moved by a prosyl- 
logism. 1 

The Disjunctive Judgment is usually described as repre- 
senting a whole divided into two or more parts mutually 
exclusive of each other; and the Disjunctive Syllogism is 
supposed to proceed either from the affirmation of one 
member to the denial of the rest, or from the denial of all 
but one to the affirmation of that one, by the Principle of 
Excluded Middle. 2 

This can scarcely be regarded as a correct analysis of 
the process, unless the two members are formally stated 
as contradictory. The Principle of Excluded Middle as- 
serts that everything is either A or not A ; that of two 
contradictories, one must exist in every object; as the 
Principle of Contradiction asserts that they cannot both 
exist. But if the two members are not stated as contra- 
dictories, if my disjunctive premise is, "All C is either A 



1 The analysis in this case may he exhibited thus : 



Hypothetical Syllogism. 
If any wax is exposed to the fire, 

it melts : 
This wax is exposed to the fire ; 
This wax melts. 



Categorical Equivalent. 
All wax exposed to the fire melts 

(because exposed) : 
This wax is exposed to the fire; 
This wax melts. 



The parenthesis indicates the material ground of the major premise. 
2 Kant, §§ 27 sqq., 77, 78; Krug, §§ 57, 84, 85; Fries, §§ 33, 59. 



200 PROLEGOMENA LOGICA. 

or B," I make the material assertion that All C which is 
not A is B. If then I reason, " This C is not A, 1 therefore 
it is B," I employ the Principle of Identity in addition to 
that of Excluded Middle. Again, if I maintain that No C 
can be both A and B, I make the material assertion that 
No C which is A is B ; and from hence to reason, " This C 
is A, therefore it is not B," requires not the Principle of 
Excluded Middle, but that of Contradiction. In the first 
case, the Excluded Middle does not lead directly to the 
conclusion, but only to the contraposition of the minor 
premise. When we deny this C to be A, this principle 
enables us to assert that it is not- A, and hence to bring the 
reasoning under the Principle of Identity. But in the sec- 
ond case, in which one of the opposed members is affirmed, 
the ground on which we deny the other is not because 
both cannot be false, but because both cannot be true. 

It may be questioned whether this second inference 
is warranted by the form of the disjunctive premise. 
Boethius calls it a material consequence ; 2 and, in spite 
of the many eminent authorities on the other side, I am 
still disposed to think he is right. But let us grant for a 
moment the opposite view, and allow that the proposition, 
"All C is either A or B," implies, as a condition of its truth, 
"No C can be both." 3 Thus viewed, it is in reality a com- 
plex proposition, containing two distinct assertions, each 
of which may be the ground of two distinct processes of 
reasoning, governed by two opposite laws. Surely it is 
essential to all clear thinking that the two should be sepa- 
rated from each other, and not confounded under one form 

1 The indefinite minor, "But it is not A," is as objectionable in this 
syllogism as in the conditional. 

2 De Syll. Hyp. lib. i.; Opera, p. 616; Cf. Galen; Isagoge Dial p. 11. 

3 Aquinas, Opusc. xlviii.; De Enunciatione, c. xiv.; Krug, Logik, § 86. 



PROLEGOMENA LOGICA. 201 

by assuming the Law of Excluded Middle to be, what it 
is not, a complex of those of Identity and Contradiction. 
Thus distinguished, the moods of the disjunctive syllogism 
are mere verbal variations from the categorical form, and 
may easily be brought under its laws. 1 

The preceding discussion may appear to some readers 
of trifling importance ; and some apology for its length 
may be thought necessary. I believe nothing to be unim- 
portant, in a logical work, which tends to mark out more 
accurately the nature of thought and its laws, to exhibit 
more precisely the formal character of logical processes, 
and to clear the subject from the remaining excrescences 
and inconsistencies with which, even in the writings of 
the best modern Logicians, it is still occasionally encum- 
bered. 2 Either Logic is not worth studying at all, or it is 
worth studying in the utmost completeness and exactitude 



i Thus : 

Modus tollendo ponens. 

Every C which is not A is B. 

Every \ 

Some v C is a C which is not A. 

This ) 
. It is B. 



Modus ponendo tollens. 
No C which is A is B. 
Every ^ 

Some r C is a C which is A. 
This ) 
It is not B. 



The first is governed by the Principle of Identity, and the second by the 
Principle of Contradiction. 

2 For example : Fries, after expressly distinguishing the Principle of 
Sufficient Reason from the other Formulae of Thought, as not being a 
principle of philosophical or formal Logic, places it in his next chapter in 
a coordinate position with them, as the distinctive law of hypothetical syl- 
logisms. Krug describes it in one place as the highest principle of syllo- 
gism in general, and in another as the special principle of a single class 
of reasonings. It is proper to speak with respect even of the errors of the 
great philosopher of Konigsburg; but perhaps even Kant was in some 
degree biassed, in his examination of logical processes, by an almost pe- 
dantic love of reproducing in every relation his four Functions of Judg- 
ment, and by the strange metaphysical theory which deduced the three 
Ideas of Pure Reason from the three kinds of dialectical syllogism. 



202 PROLEGOMENA LOGICA. 

of which it is susceptible. The length to which these 
remarks have run is justified, indeed demanded, by the 
eminence of the authors from whom the writer has ven- 
tured to dissent, — authors whose mere assertions in mat- 
ters of logical science are not to be lightly regarded nor 
hastily departed from. Even if the views here advanced 
should be found, on examination, to be less tenable 
than the author believes them to be, they will not have 
been without their use, if, by calling the attention of others 
to one or two of the weaker defences of the received doc- 
trines of Formal Logic, they should indirectly lead to a 
more satisfactory vindication of the positions assailed. 

It only remains to sum up as briefly as possible the re- 
sults of the present chapter. Formal or Logical Necessity 
is dependent on one negative condition, and on three 
positive laws. The negative condition, or sine qua non 
of thought in general, is contained in the Principle of 
Sufficient Reason, which, however, in this relation, belongs 
to Psychology, and not to Logic ; being only a general 
statement of the conditions under which, in the existing 
constitution of man's mind, thought is possible ; — its de- 
j)endence, that is to say, on a higher thought, or on a fact 
of intuition. The three positive laws, or fundamental 
principles, assumed by Logic, as regulating all its actual 
processes, are those of Identity, of Contradiction, and of 
Excluded Middle; the last, however, operating in most 
cases in subordination to the other two. These three are 
the highest and simplest forms of identical judgments, to 
one of which all analytical thinking may ultimately be 
referred : and all pure thinking may be shown, on psycho- 
logical grounds, to be of a strictly analytical character. 
The necessity arising from these laws is that of the har- 
mony of thought with itself, — of its conformity to its own 



PROLEGOMENA LOGICA. 203 

ruling principles ; as the forms of necessity noticed in the 
previous chapters were those arising from the relation of 
thought to the laws and condition of intuition, — the re- 
quisite harmony of the several mental faculties one with 
another. These two harmonies constitute respectively 
Formal and Material Truth. Truth, relatively to man, 
cannot be defined as consisting in the conformity of knowl- 
edge with its object; for to man the object itself exists 
only as it is known by one faculty or another. Material 
Truth consists rather in the conformity of the object as 
represented in thought with the object as presented in 
intuition ; and of this no general law or criterion can be 
given ; its essence consisting in its adapting itself in every 
case to the diversities of this or that special presentation. 
But Logical Truth, which consists in the conformity of 
thought to its own laws, can be submitted to those laws as 
general and sufficient criteria ; criteria, however, not of the 
real and existent, but of the thinkable and possible. Of 
actual truth it furnishes one element only, which becomes 
truth or not in combination, according as, upon further 
examination, it is found to be in conformity or at variance 
with the coordinate decisions of experience. By the same 
criteria we shall also be able to determine the logical or 
extralogical character of any portion of the contents of 
existing treatises on the science ; according as it is a de- 
duction of pure thinking from given materials, or a mixed 
process, combining the act of thought with the acquisition 
of further empirical data. On the distinction established 
between material and formal thinking, some further obser- 
vations will be made in the next chapter. 



CHAPTER VII. 

ON THE MATTER AND FORM OF THOUGHT. 

The distinction adopted between Matter and Form in 
common language, relatively to works of Art, will serve 
to illustrate the character of the corresponding distinction 
in Thought. The term Matter is usually applied to what- 
ever is given to the artist, and consequently, as given, does 
not come within the province of the art itself to supply. 
The Form is that which is given in and through the 
proper operation of the art. In Sculpture, for example, 
the Matter is the marble in its rough state as given to 
the sculptor; the Form is that which the sculptor, in the 
exercise of his art, communicates to it. 1 The distinction 
between Matter and Form in any mental operation is 
analogous to this. The former includes all that is given 
to, the latter all that is given by, the operation. In the 
division of notions, for example, whether performed by an 
act of pure thinking or not, the generic notion is that 
given to be divided ; the addition of the difference in the 
act of division constitutes the species. And, accordingly, 
Genus is frequently designated by logicians the material, 
Difference, the formal part, or the Species. So, likewise, in 
any operation of pure thinking, the Matter will include all 
that is given to and out of the thought; the Form is what 
is conveyed in and by the thinking act itself. 

1 See Fries, System der Logik, § 19. His division corresponds to the 
above, though based on a somewhat different principle. 



PROLEGOMENA LOGICA. 205 

The same analogy may be carried on in relation to what 
are called material and formal processes of thinking. It 
may happen on certain occasions that the marble given to 
the sculptor is insufficient for the completion of the statue. 
It becomes necessary, therefore, to suspend the artistic 
process itself, in order to obtain additional material ; and 
this provision of new material the artist does not under- 
take purely as a sculptor. So in relation to any process 
of thinking. The empirical data requisite for an act of 
conception, judgment, or reasoning, may be insufficient, 
and require the addition of fresh material not furnished 
by the mere act of thinking. The operation in this case 
is one of mixed or material thinking ; i.e., of thinking pre- 
ceded by an appeal to experience for the provision of 
further data ; and this appeal is no part of the duty of the 
logician, as such. Whereas, if the materials originally 
given are alone sufficient to necessitate, in obedience to 
the laws of thought, an act of conception, judgment, or 
reasoning, the process is properly distinguished as one 
of pure or formal thinking. 

Notwithstanding this analogy, it is in many respects im- 
portant that the matter and form of a thought should not 
be confounded with material and formal thinking respect- 
ively. Thinking is not always formal because its product 
has form, nor does the presence of a form in the antece- 
dent of thought always necessitate a formal process in 
consequence. The sculptor, to continue our image, may 
ultimately complete his work with all the form and finish 
of art : it does not therefore follow that all his material 
must have been given to him at once in the first instance. 
Or he may have carved with exactness one subordinate 
figure of a group : it does not therefore follow that his 
material is sufficient to enable him to complete the whole. 

18 



206 PROLEGOMENA LOGICA. 

The present chapter is intended to point out more clearly 
the distinction and relation between the form of thought 
and formal thinking. 

The antithesis of matter and form, — the objective and 
the subjective, — the variable and the permanent, — the 
contingent and the necessary, runs through all the phenom- 
ena of consciousness. The manifold elements presented 
by any object of consciousness constitute the matter; the 
relations which the mind, acting by its own laws, insti- 
tutes between the several elements as it combines them 
into an object, constitute the form. 1 In this point of view, 
Space and Time are called by Kant the Forms of the Sensi- 
bility in general, external or internal; the objects of the 
former being necessarily regarded by the mind as lying 
out of ourselves in Space, the objects of the latter, as 
succeeding one another in Time. These may thus be 
regarded as the subjective conditions under which sensi- 
bility in general is possible. The same antithesis may be 
carried through those special acts of consciousness, in 
which the understanding operates, whether in conjunction 
with the presentative faculties, as in an act of mixed think- 
ing, or representatively, as in pure thinking. A savage, 
to adopt an illustration of Kant's, 2 sees a house in the dis- 
tance, not knowing what it is. It is thus present to him 
only as an intuition in space. But the very same complex 
phenomenon is presented to a man who knows it to be 
a building designed for the habitation of men. To the 
same sensible data the understanding now adds its own 
contribution, by which the several presentations of sense 
are combined into one whole, under the general notion of 



1 See Kant, Kritik der r. V. p. 32 (ed. Rosenkranz). 

2 Logik, Einleitung v. 



PROLEGOMENA LOGICA. 207 

a house. The sensible attributes here constitute the mat- 
ter; their union in a concept is the form. 

In Thought, as in Intuition, there is thus a variable and 
a permanent, an objective and a subjective element, a 
matter given to the thinker, a form communicated by the 
thinking act. In respect to the matter, concepts differ one 
from another, as being composed of this or that variety 
of given attributes. In respect of the form, all agree, as 
being a collection of attributes constituting an object. 
The universal conditions under which attributes are con- 
ceived in this relation have been pointed out in the last 
chapter, as the Principles of Identity, Contradiction, and 
Excluded Middle. From these three laws we may deduce, 
with some amendment, the Forms which have been re- 
garded by logical writers as distinctive of the Concept 
proper. 1 The concept is necessarily conceived as one, as 
one out of many, and as constituting loith the many a 
universe of all that is conceivable. From the last of these 
three conditions it follows that the concept must possess a 
generic or universal feature, by which it is characterized 
as a concept in general, or a member of the conceivable 
universe. From the second it follows, that it must also 
possess a differential or peculiar feature, by which it is dis- 
tinguished from all others. And from the first it follows, 
that these two features must be united in a single whole. 
Hence every concept, as such, must possess in some degree 
the attributes of distinctness, as having complex contents ; 
of clearness, as being, by one portion of its contents, dis- 
tinguishable from other notions ; and of relation to a pos- 
sible object of intuition, inasmuch as the unity of a complex 

1 See Kant, Logik, § 2; Fries, System, der Logik, § 20. The former places 
the form of a concept in its universality ; the latter adopts the same view, 
subdividing universality into extension and comprehension. 



208 PROLEGOMENA LOGICA. 

notion depends not on a mere juxtaposition of terms, but 
upon its being the representative of one object. 1 These 
three forms may be otherwise denominated (for the differ- 
ence is merely verbal) comprehension, limitation, and ex- 
tension. As having complex contents, every concept 
comprehends certain attributes; as distinguishable from 
others, it is limited by its specific difference ; and, as rep- 
resentative of a class of possible objects, it has a certain 
field over which it is extended. The forms of the concept 
proper may thus be indifferently enumerated as Distinct- 
ness, Clearness, and Relation to an object; or as Compre- 
hension, Limitation, and Extension. 

The matter and form of Judgments may be dis- 
tinguished in the same manner as those of Concepts. 
Omitting those judgments which involve merely the 
enumeration of the attributes comprehended in a concept 
(the analytical or explicative judgments of Kant), which 
may be more properly classed as acts of Conception ; and 
confining ourselves to those in which the contents of the 
given concepts are distinct from each other (the syntheti- 
cal or ampliaiive judgments of Kant), we may distinguish, 
as before, between the preexisting materials, which must 
be given before the act of judging takes place, and the 
additions contributed by the act itself. 

Thus, to take an example adduced in a former chapter : 
If I poise a piece of gold in my hand, in order to ascertain 
whether it is heavy, the presented phenomena belong to 
distinct acts of sensation. The evidence of sight attests 

1 Arist. Metaph. vi. 12. 'E7rl fxkv yap rod fofrpcoiros kol\ Xevubv iroXXa /xeu 
iaTLV, '6rav jut] virapxy frarepoj &arzpov, ev Se, orav virdpx'p Kal ird&ri ri to 
viroKei/xevoy 6 av&pooiros' r6re yap ev yiyvsrai Kal tcriv 6 \evicbs frvfrpcoiros. 
Ibid. vii. 6. 'O 8' 6pio~[xbs Aoyos icrilv eis ov o~vvdeo~/j.a) ndfrairep 7) 'lAids, 
a\Xa rep tvbs efoai. 



PROLEGOMENA LOGICA. 209 

the presence of a round, yellow, shining body; the evi- 
dence of touch, or rather of muscular pressure, attests its 
weight. To unite these attributes as belonging to one 
and the same thing, is an act, not of sensation, but of 
thought. The mere sensation, aided by the concepts, 
presents us with three things — the body which, is seen, 
and a certain temporal and local juxtaposition of the two. 
To combine the present attributes as belonging to one 
thing — to pronounce that it is the gold which is heavy 
— is an act of thought constituting a judgment. Here, 
then, we have one form of the judgment expressed in the 
copula, "Gold is heavy:" this indicates the identification 
of the two concepts as related to a common object ; an 
identification usually known as the Quality of the Judg- 
ment. 

The same is the case with the Quantity of Judgments. 
I see a number of balls lying on a table, and pronounce at 
once that they are all white ; I see another collection, and 
assert in like manner that some are white and some black. 
Here the senses, even when aided by the concepts in 
distinguishing the balls as such, yet present to us only 
individual objects. This, this, and this, are within their 
province ; but they know nothing of all or some. It is by 
an act of thought that the several individuals are regarded 
as constituting a whole, and a judgment pronounced con- 
cerning that whole or a portion of it. 

A third Form of the Judgment, as indeed of all thought, 
is Limitation. In predicating one notion of another, I at 
the same time necessarily exclude everything to which 
that predicate is opposed, and thereby limit the subject to 
one alone of those contradictory determinations which 
make up the universe of thought. In asserting, for exam- 
ple, that gold is heavy, I as much exclude it from the class 

18* 



210 PROLEGOMENA LOGICA. 

of imponderables as I include it in that of bodies pos- 
sessing weight. The canon that predication is limita- 
tion is now indeed generally admitted as an axiom in 
philosophy; 1 and the various metaphysical systems of 
modern Germany, since the days of Kant, may be briefly 
described as so many attempts to evade the consequences 
of this principle, by constructing a philosophy of the un- 
limited on a basis independent of logical predication. 

The two forms of Quantity and Quality are generally 
recognized by logicians of the school of Kant. To these 
are added two others, Relation and Modality. The former 
of these includes the three subdivisions of Categorical, 
Hypothetical, and Disjunctive, and is necessarily included 
among the forms of thought by those who adopt Kant's 
theory of the nature of these three kinds of jjropositions. 
But the view which has been taken of these in the last 
chapter precludes the admission of Relation as a distinct 
form from Quantity and Quality. Disjunctive judgments 
have there been treated as reducible to Categorical forms ; 
and Hypothetical as containing, not a judgment, properly 
speaking, but a consequence, formal or material. In this 
case, the relation is not between the different parts of a sin- 
gle judgment, but between two judgments, one dependent 
on the other. The judgment proper being thus confined 
to the categorical form only, Relation becomes only a gen- 
eral expression for the connection of subject and predicate 
under certain conditions of quantity and quality, and thus 
is not a special form of judgment, but a term equivalent 
to Form in general. 

1 See for example, among others, Fichte, Ueber den Grund unseres Glau- 
bens an eine gottliche Wellregierung, p. 16 ( Werke, v. p. 187); Gerichtliche 
Verantwortung, p. 47 ( Werke, v. p. 265); Bestimmung des Menschen ( Werke, 
ii. p. 304); Hegel, Logik, P. i. b. ii. ch. 2, P. ii. ch. 2 ( Werke, iv. p. 26, v. 
p. 70). 



TROLEGOMENA LOGICA. 211 

As regards Modality, judgments, according to Kant, are 
of three kinds: problematical, assertorial, and apodeictical. 
The first are accompanied by a consciousness of the bare 
possibility of the judgment ; the second, by a conscious- 
ness of its reality ; the third, by a consciousness of 
its necessity. Modality is thus dependent on the man- 
ner in which a certain relation between two concepts 
is maintained, and may vary according to the state of 
different minds ; the given concepts, and consequently the 
matter of the judgment, remaining unaltered. 1 These 
grounds are fully sufficient to establish modality, in the 
extent to which it is acknowledged by Kant and by Aris- 
totle, 2 as, in a psychological point of view, belonging to 
the form, not to the matter, of judgment. It is conveyed 
in the act of judging, not given in the preliminary mate- 
rials, and affects the copula, not the predicate. But the 
forms cognizable by Psychology must not be confounded 
with the forms cognizable by Logic. The latter science 
is not concerned, as is sometimes maintained, with the 
Forms of Thought in general, but only with the Forms 
of Thought as related, to pure or formal thinking. The 
meaning of this limitation will appear more clearly in the 
sequel. In this point of view, Modality stands on a very 
different footing from Quantity and Quality. In cases 

1 Kant, Logik, § 30. 

2 Aristotle, in the T>e Interpretatione, ch. 12, enumerates four modes of 
judgment: the necessary, the impossible, the contingent, and the possible. 
The addition of the true and the false is, I think, founded on a misinter- 
pretation. These modes he reduces, in the Prior Analytics, i. 2, to the ne- 
cessary and the contingent (rov e| avdyKrjs virdpxeu' and rov eVSe'xeo'&cu 
virapxeiv). These, with the addition of the pure judgment (rov virdpx^v) , 
correspond to the division of Kant. The spurious modes admitted in 
abundance by the scholastic logicians are not forms of the judgment, but 
modifications of one of its terms only. They affect, that is, the subject 
alone, or the predicate alone, not the relation between the two. 



212 PROLEGOMENA LOGICA. 

where a modal conclusion is drawn from modal premises, 
it is only the form of the conclusion as a judgment that 
differs from that of the pure syllogism : its relation to 
the premises as a conclusion from them, consequently 
the entire form of the reasoning, is the same in both. 
Whereas, by the substitution of a negative premise for 
an affirmative, or of a particular for a universal, the con- 
clusiveness of the premises as necessitating a consequence, 
and hence the whole form of the reasoning, will, in most 
cases, vanish altogether. For this reason, Modality, though 
psychologically a form of judgment, is not one of those 
forms that properly fall within the province of Logic. This 
will be made clearer when we come to treat of the matter 
and form of syllogisms. 1 

As conception furnishes the material for an act of judg- 
ment, so judgment furnishes the material for an act of 
reasoning. The Matter of the inference consists in the 
several propositions of which it is composed, and which 
vary in every different instance : its Form appears in the 
manner in which those propositions are invariably thought 
as connected together as premises and conclusion. This 
connection consists in the recognition of a relation of 
identity or contradiction between the terms as given in 
the antecedent and those connected by the act of reason- 
ing in the consequent. The Forms of the Syllogism may 
thus be determined by the following question : Given two 
judgments (no matter what may be their material signifi- 
cation), what relations must exist between them to warrant 
us in inferring a third judgment as their consequent? 

In the first place, the premises and conclusion must 
stand to each other in the relation of condition and con- 

1 On the disputed question of the relation of Modals to Logic, some fur- 
ther remarks will be found in the Appendix, note H. 



PROLEGOMENA LOGICA. 213 

ditioned. As the predicate of a judgment limits and 
determines the subject, so the premises of a syllogism 
must limit and determine the conclusion. Limitation is 
thus a form of reasoning, as of all thinking ; the act of 
reasoning being such as to determine the mind to one 
actual conclusion out of two contradictory possibilities. 

In the second place, since the terms of the conclusion 
are not compared together directly, but through the 
medium of a third, it is necessary that this third concept 
should be compared with each of the others. This com- 
parison, as we have seen in the last chapter, results in a 
relation either of identity or contradiction ; the objects 
denoted by the two concepts being pronounced identical 
when the premise is affirmative, and contradictory when 
it is negative ; and a similar relation being consequently 
inferred to exist between the concepts compared together 
in the conclusion. The Forms which the Syllogism ex- 
hibits in these relations are those of Mood and Figure, 
affirmative or negative, which show us what relations of 
identity or contradiction in the premises of a Syllogism 
may legitimately determine a similar relation in the con- 
clusion. 

Inferences, as well as judgments, are in some cases the 
result of an act of mixed thinking; of reasoning, that is, in 
conjunction with an appeal to experience. This is some- 
times distinguished by logicians as material consequence ; 
the strictly logical operation being designated formal. In 
the earlier portion of the present chapter it has been neces- 
sary to avoid this nomenclature ; the object having been 
to show that in every act of thought, pure or mixed, the 
product exhibits the distinct features of a matter given to, 
and a form given by, the thinker. The matter and form 
of thought are thus by no means coextensive with material 



214 PROLEGOMENA LOGIC A. 

and formal thinking ; and it becomes, therefore, necessary 
to examine separately the propriety of these last expres- 
sions, and to determine what is the exact sense in which 
Logic is defined to be a Formal Science. 

The distinction between formal and material, or, as for 
the present it is better to term them, between pure and 
mixed thinking, has not in general been consistently fol- 
lowed out by logicians. They have allowed the existence 
of material consequences in which the conclusion does not 
follow from the given premises, but requires additional 
data from experience; and these they have rightly regarded 
as extralogical ; but they have not observed that the same 
distinction is applicable to Apprehension and Judgment, 
as well as to reasoning; that there are pure and mixed 
concepts and judgments, as well as pure and mixed rea- 
sonings ; and that in every case the province of Logic is 
with the first only. In consequence of this, the province 
of Logic has been by some too much widened, and by 
others too much narrowed. On the one side, we are told 
that it can remedy indistinctness of apprehension and fal- 
sity of judgment — a pretension which, announced without 
limitation, is perfectly absurd ; and on the other side, it 
has been described as concerned with the operation of rea- 
soning only; apprehension and judgment being considered 
only in subordination to this. Neither view has been con- 
sistently carried out. The advocates of the former ought 
to have included within the province of Logic, Induction, 
Analogy, and the whole field of probable reasoning; while 
the advocates of the latter ought to have extended the 
signification of the term reasoning, so as to include those 
forms of pure thinking which are governed by the same 
laws as the formal syllogism. 

It would be more correct to distinguish, with regard to 



PROLEGOMENA LOGICA. 215 

all the three operations of the understanding, between 
those errors which arise from a defect in the thought itself, 
and those which arise from a defect in the corresponding 
experience. For example : my conception of a particular 
flower is obscure, when I have not noticed it so closely as 
to be able to distinguish it as a whole from certain others ; 
it is indistinct, when I know it as a whole, but have not 
analyzed it so minutely as to be able to enumerate its 
botanical characteristics. In these cases the defect is em- 
pirical, and can only be remedied by closer attention to 
the individual flowers of that kind. But, on the other 
hand, my conception may be obscure, as containing attri- 
butes inconsistent with the existence of its object as an 
individual whole ; or it may be indistinct, as containing 
attributes incapable of coexisting with each other as parts 
of a whole. Thus we may be told to conceive a flower of 
no color at all, or a flower which shall be both red and 
white on the same part of the same leaf. In these cases 
the defect is in the thought itself; and, accordingly, Logic 
is competent to declare the supposed object inconceivable. 
Again, a judgment may be empirically false, as asserting a 
combination of attributes never actually found in experi- 
ence; as if it is asserted that a horse has five legs. It 
may be logically false, as coupling together attributes which 
contradict each other; as if it is asserted that a quadruped 
has five legs. In the former case, I can contradict the as- 
sertion only by an appeal to the experience of all who are 
acquainted with the animal ; in the latter, I can contradict 
it on logical grounds, as false in the thought itself. An 
inference, in like manner, may be empirically inconsequent, 
as grounded on a relation of phenomena not invariable in 
nature ; it may be logically inconsequent, as deduced from 
premises not necessitating it by the laws of thought. Thus, 



216 PROLEGOMENA LOGICA. 

if I am asked whether this particular fall of the barometer 
is a ground for asserting that it will rain within twelve 
hours, I can only reply, as a logician, that it is so, if all 
falls of the barometer are so ; but whether this is the case 
in fact, cannot be decided by logic, but by experience. On 
the other hand, if it be expressly stated that some falls only 
of the barometer are indications of rain within twelve hours, 
I can at once decide that it is logically inconsequent to 
reason from a merely partial rule to any single instance : 
the rain may in this case be expected with more or less 
probability, but it cannot be inferred as a certainty. 

It thus appears that, in all the three operations of the 
understanding, Logic is equally competent to detect their 
internal vices, as thoughts transgressing their own laws; 
and that in all it is equally incompetent to detect their 
external vices, as thoughts inconsistent with experience. 
It can detect the inconceivability of a notion, the self- 
contradiction of a judgment, the inconsequence of a con- 
clusion, as not necessitated by given premises. It cannot 
supply the empirical deficiencies of a notion, nor determine 
the real existence of its object; it cannot ascertain the 
truth or falsehood of a judgment as a statement of a fact; 
it cannot decide as to the necessary sequence of a conclu- 
sion from understood premises, or the probability of its 
truth where the given premises are insufficient to necessi- 
tate it by the laws of thought. It remains to ascertain 
the exact meaning of the expressions formal and material 
thinking, as applied respectively to those operations which 
do or do not fall within the province of Logic. 

Law and Form, though correlative terms, must not, in 
strict accuracy, be used as synonymous. The former is 
used properly with reference to an operation ; the latter, 
with reference to its product. Conceiving, Judging, Rea- 



PROLEGOMENA LOGICA. 217 

soning, are subject to certain laws; Concepts, Judgments, 
Syllogisms, exhibit certain forms. But the laws of thought 
are not always competent to determine its form, as has 
been already shown in the case of all the products of mixed 
thinking. In a synthetical judgment, for example, the 
laws of thought can determine only its possible truth, which 
equally implies its possible falsehood ; thus leaving it alto- 
gether undecided whether the form of the judgment should 
be affirmative or negative, universal or particular. The 
form in all these cases is determined by that universal ten- 
dency of the human mind, which has been noticed in a 
former chapter, the tendency to regard physical phenomena 
as indicating the existence of a substance or a cause similar 
to that of which we are directly conscious in our own men- 
tal states and operations. It is thus that, when experience 
presents certain phenomena in juxtaposition, the mind is 
invariably led to regard them as attributes of one and the 
same substance ; and this constitutes the form of all mixed 
concepts and judgments. And in like manner, when one 
phenomenon is the invariable consequent of another, the 
mind is irresistibly led to regard them as respectively cause 
and effect; and this constitutes the form in all cases of 
mixed inference. The same tendencies which thus co- 
operate with the presentations of experience in the acts of 
mixed thinking, cooperate in like manner with the laws of 
thought in acts of pure thinking. In the former case, the 
attributes are given as empirically related as intuitions; 
in the latter, they are given as logically related as thoughts; 
and in both they are regarded as mutually related to some 
unknown substance or cause. But that these tendencies, 
however universal or irresistible, cannot properly be re- 
garded as laws of thought or of intuition, is manifest from 
the fact, that they furnish no criterion for determining the 

19 



218 PROLEGOMENA LOGICA. 

legitimacy or illegitimacy of any product. Thoughts, 
whether empirically true or false, whether logically sound 
or unsound, in this respect present precisely the same 
features. An assertion, false in point of fact, or self-con- 
tradictory in point of thought, contains, as regards the 
supposed relation of attributes to a common substance, 
precisely the same form as one logically and empirically 
valid. The Principles of Substance and Causality are thus 
rather negative conditions than positive laws of thought. 
They have a psychological relation to thought as it actu- 
ally exists, explaining and accounting for the fact of its 
invariably assuming a certain form ; but they have no logi- 
cal relation to thought as it ought to be, and furnish no 
criterion of its validity in any special instance. 

Logical or pure thinking is not, therefore, called formal, 
because its product exhibits a form ; for the coexistence 
of matter and form is common to* all thought, and to all 
spurious imitations of thought. But the justification of 
the terms formal and material, as applied to pure and 
mixed processes of thinking, is to be found in the circum- 
stance, that in the former the act of thought is based on 
the form only of the preliminary data, without reference 
to the particular matter ; while, on the other hand, matter 
is necessarily taken into account in every process of 
mixed thinking. To an act of logical conception, for ex- 
ample, it is not necessary to examine in any case the 
special character of the attributes, as having been actually 
combined in experience ; but only that they should be 
compatible with the possible existence of an object in 
space or time. In an act of logical judgment, one of the 
given concepts being always comprehended in the other, 
it is indifferent of what special attributes either is com- 
posed, provided they possess sufficient clearness and dis- 



PROLEGOMENA LOGICA. 219 

tinctness to enable the mind to discern the relation 
between them. In an act of logical reasoning, the validity 
of the conclusion depends solely on the quantity and 
quality of the given premises, without any reference to 
the particular terms of which they are composed. In all, 
so long as the formal relation of the data remains the 
same, the matter may be changed as we please, without 
affecting the logical value of the thought. In mixed 
thinking, on the other hand, the matter is of principal im- 
portance. To determine that this or that object of con- 
ception actually exists, that this or that judgment is in 
accordance with experience, that this or that inference is 
sufficiently probable to furnish a reasonable motive to 
action, we require to be guided by a knowledge of the 
nature and circumstances of the particular object in ques- 
tion. And it is for this reason that all examples of logical 
thinking are better expressed by means of arbitrary sym- 
bols than of significant terms ; not that it is in any case 
possible to think without some matter or other, but be- 
cause it is wholly indifferent what matter we may at the 
time be thinking about ; and, therefore, by employing an 
unmeaning sign, indifferently representative of any object 
of thought, we are enabled to clear the process from any 
accidental admixture of material knowledge, and to ex- 
hibit the form alone in its proper relation to the laws of 
thought. 

In accordance with the view here given of Form and 
Formal Processes, it will be proper to modify slightly 
some of the definitions of Logic given by those philos- 
ophers whose views have been principally followed in the 
present work. Logic, to omit less accurate views of its 
nature, has been defined as the Science of the bare Form 



220 PROLEGOMENA LOGICA. 

of Thought, 1 or as the Science of the Formal Laws of 
Thought; 2 ' — definitions which, though substantially ap- 
proaching far nearer to the truth than any antagonist 
view, still leave something to desire in point of verbal 
accuracy. The term formal strictly belongs rather to the 
process of pure thinking than to the laws by which it is reg- 
ulated, or to the science which takes cognizance of them ; 
and Logic is not the science of the Forms of Thought in 
general, but only of such as are subservient to other pro- 
cesses of formal thinking. Other forms, such as modality, 
fall without the province of Logic, and within that of 
Psychology ; to which latter science, indeed, all the forms 
and laws of thought belong in their relation to the consti- 
tution of the thinking subject. To Logic, on the other 
hand, belong the same forms and laws in relation to those 
acts and products of pure thinking which are suggested 
by the one and governed by the other. If, therefore, 
slightly altering the language of the above definitions, we 
define Logic as the Science of the Laws and Products of 
Pure or Formal Thinking, 3 we shall express with tolerable 
accuracy its character and province, according to the views 
advocated in the preceding pages. 

1 Kant, Logik, Einleitung I. ; Hoffbauer, Logik, § 17. 

2 Sir W. Hamilton, Discussions, p. 119. 

3 This coincides nearly with the definition given by Sir W. Hamilton 
(Beid's Warks, p. 698), The science of the laws of thought as thought. 



CHAPTER VIII. 

ON POSITIVE AND NEGATIVE THOUGHT. 

Logic has been described by Kant as the science of the 
necessary laws of the understanding and of the reason. 
Psychologically, the propriety of this division of the men- 
tal faculties has been called in question by eminent critics. 1 
And in a logical point of view it is untenable, if, as I have 
endeavored to show, judgment and reasoning, in so far as 
they are logical processes, are both governed by the same 
laws, and must be referred to the same faculty. In the 
present chapter, however, it is proposed to examine an- 
other expression of the same definition, and to inquire in 
what sense the Laws of^Thought can properly be called 
necessary. Kant employed this term to distinguish the 
laws of thought in general from those of thought as em- 
ployed upon any definite class of objects ; it being optional 
with every man, and therefore contingent, whether he shall 
exercise his understanding on one class of objects rather 
than another. 2 This distinction I have preferred to express 
in other words, by separating pure or formal from mixed 
or material thinking ; but the Kantian phraseology may 
serve to introduce a subject, the right understanding of 
which is of considerable importance in Logic : the differ- 

1 Among others, by Sir William Hamilton (Discussions, p. 17), and by M. 
Cousin (Lecons sur la philosophie de Kant, L. vi.). 

2 Kant, Logik, Einleitung I. 

19* 



222 PROLEGOMENA LOGICA. 

ence, namely, between positive and negative thinking. 
The phrase necessary laws of thought, if such language is 
allowable, ought to imply that we cannot think at all ex- 
cept under their conditions ; and yet it is notorious that 
such laws are daily transgressed, that nothing is more com- 
mon than illogical reasoning. To reconcile the language 
with the fact is the object of the following observations. 

Illogical reasoning may be of two very different kinds. 
It may violate the laws of thought in cases where they are 
applicable, or it may endeavor to extend them to cases 
where they are not applicable. The offence in the former 
case consists in attempting to draw a conclusion opposed 
to that which the laws require ; in the latter, in attempt- 
ing to draw a conclusion where none can be legitimately 
inferred. Thus we may, verbally at least, reason, " All A 
is B ; all C is A ; therefore no C is B." Or we may reason, 
" All A is B ; some C is not A ; therefore some C is not 
B." If the laws of thought are in the strict sense ne- 
cessary, i. e., obligatory upon every act of thinking, it will 
follow that these supposed reasonings are neither of them 
acts of thought at all. 

It is, of course, always possible to compose a verbal rep- 
resentation of a thought in which the rules of Logic shall 
be violated, and to understand fully the meaning of each 
word of which it is composed. The test, however, of the 
reality of a thought does not lie in the possibility of asser- 
tion, but in the possibility of conception y 1 in the power, 
that is to say, of combining the given attributes in a single 
image representative of an individual object of intuition. 2 

1 Ov yap irpbs rbv c£&j Xoyov 7] air6dei£is, aWa. irpbs rbv kv rfj tyvxVi 67re ^ 
ouSe cruXXoyia/j.6s. 'Ael yap ivriv iuarrjuat irpbs rbv e£a> x6yov, aXXa irpbs 
rbv ecrea Xoyov ovk ael. — Arist. Anal. Post. I. 10, 6. 

2 It will be necessary here to bear in mind what has been observed before, 



PROLEGOMENA LOGICA. 223 

I may make use of the words a round square, or a bilinear 
figure / but the terms imply no conception, because the 
attributes cannot be united in an image. These words, 
therefore, are not the signs of thought, but only express the 
negation of any object on which thought can be exercised. 1 

And such, in ultimate analysis, will be seen to be the 
case with all verbal combinations in which the laws of 
formal thinking are violated ; whether directly, by denying 
their authority in cases to which they are applicable, or 
indirectly, by attempting to apply them to cases where 
they are not applicable. The only difference between 
these two offences is, that in the former case the product 
is no thought whatever ; in the latter, it is -not that kind 
of thought which it professes to be. 

Let us suppose, for example, a syllogistic conclusion 
verbally asserted, the reverse of that which the laws of 
thought require ; such as, "All A is B, all C is A, therefore 
some C is not B." This reasoning supposes the possibility 
of conceiving a C which shall at the same time be B and 
not B. Tried by this test, the form of words is ascertained 
to be representative of no thought at all. 

On the other hand, in a case where the law of reasoning 
is not applicable, as in the apparent syllogism, " All Y is 
[some] Z, no X is [any] Y, therefore no X is [any] Z," the 
thought is annihilated as a syllogism only : as a mere judg- 
ment, the concluding proposition may or may not be true ; 
and there is no impossibility in conceiving an X which is 
neither Y nor Z. But, as a syllogism, it maintains that X 
is not Z, because it is not Y; in other words, that nothing 

that all conception implies imagination, though all imagination does not 
imply conception. See p. 33. 

1 See, on this subject, an excellent note in Sir W. Hamilton's edition of 
Beid, p. 377. 



224 PROLEGOMENA LOGIC A. 

which is not Y can be Z, or that all Z is Y; — an assertion 
which again involves a contradiction of the major premise, 
which, in asserting that all Y is some Z only, implies at 
the same time that some Z is not Y. This contradiction 
is not so apparent in the ordinary form of the affirmative 
proposition, in which the predicate is expressed as indefi- 
nite, though thought as particular ; and thus the elliptical 
and imperfect language of common Logic has caused to be 
overlooked the important truth, that illogical thinking is 
in reality no thinking at all. 

The language of this chapter may recall to the mind of 
the reader a distinction made in an earlier portion of the 
present work, between positive and negative ideas. A 
comparison of the two cases will serve to show that the 
expression negative thinking, or negation of thought, is 
properly applicable to both, though in different relations 
and on different grounds. Positive thinking implies two 
conditions : firstly, the material condition, that certain at- 
tributes be given as united in a concept ; secondly, the 
formal condition that the concept be capable of individu- 
alization, i. e., that the attributes be such as can coexist in 
an object perceived or imagined. If either of these con- 
ditions be wanting, we are deficient in the sine qua non of 
actual thought. A given form of words may thus in two 
different ways be void of a thought corresponding. We 
may be unable to conceive separately one or more of the 
attributes given, or we may be unable to conceive them in 
combination. The former is the case when we have never 
been personally conscious of the said attribute as presented; 
the latter is the case when the several presentations are 
incompatible with each other. 

From defect in the first of these conditions, a man born 
blind may be said to have a negative idea of light, which 



PROLEGOMENA LOGICA. 225 

he knows only as something different from darkness, and, 
consequently, of the various colors, which are different 
modifications of light ; and any man, in like manner, has 
but a negative idea of a color which he has not actually 
seen. 1 The blind man may be able to distinguish a sphere 
from a cube, by touch ; but if he is told that the ball which 
he has in his hand is white, he cannot connect the word 
with any sensation of which he has been at any time con- 
scious. And in like manner, a man who has seen white 
objects only has no idea of red; he knows it only as some 
color which he has not seen. In this manner it is that we 
have negative ideas only of many of the objects on which 
men most boldly speculate. Such is the case with all our 
speculations on causality r , as existing apart from the con- 
scious exertion of power ; on substance, other than as a 
conscious self; on consciousness in general, apart from the 
conditions of space and time. Of these we can only speak 
as a causality which is not our causality; as a substance 
different from our substance ; as a consciousness unlike our 
consciousness. 2 The same is the case with all the spec- 
ulations of our reason concerning infinity and infinite 
attributes as such. By removing the condition of limi- 
tation, we remove the only condition under which such 
attributes have ever been presented to our consciousness. 
Further speculation is not thought, but its negation. 

1 In the first of these instances the negative idea is so obscure as to be 
tantamount in its actual result to no idea at all. Still the corresponding 
state of mind is not one of pure quiescence, or mere absence of thought. 
A blind man who had lived all his life among a nation of blind men, and 
who had thus never been led to infer the existence of visible objects at all, 
would be in a different state from one who is continually told of things 
which he is unable to see, and whose mind is consequently roused to an 
effort, though an ineffectual one. 

2 Cf. Damiron, Psychologie, vol. ii. p. 221. 



226 PROLEGOMENA LOGICA. 

The second condition fails in cases of illogical thinking, 
all of which may be shown ultimately to annihilate them- 
selves by involving a contradiction. And in these cases 
the attempt to individualize »the thought furnishes at once 
a decisive criterion of its negative character. In the for- 
mer instances, the thought is only ultimately discovered 
to be unattainable from the failure of every attempt to 
realize it ; in the present case, the attributes can be im- 
mediately determined to be unthinkable, as mutually 
destroying one another. The former may be distinguished 
as materially or relatively negative from the absence of 
the requisite data for thinking ; the latter are formally or 
absolutely negative, as containing data which offend against 
the universal laws of human thought. The former might 
become positive if man were furnished with a new sense, 
or any additional faculty of intuition ; the latter could 
only become so by a complete inversion of the existing 
constitution of his mind. The negative character of the 
first is shown by Psychology, which ascertains empirically 
the limitations to which the mind is subject in the accu- 
mulation of materials for thinking ; the negative character 
of the second is shown by Logic, which lays down a priori 
the conditions to which all materials, whencesoever de- 
rived, must be subjected in the formation of thought. 

It is of the utmost importance to distinguish these two 
kinds of negative thinking, the material or psychological, 
and the formal or logical, from each other. No error in 
philosophy is more frequent in its occurrence, or more per- 
nicious in its results, than a confusion on this point. Men 
are apt to mistake the absence of the materials for one 
thought for the presence of materials for its opposite ; — 
to imagine that it is all one to be unable to think of an 
object as existing, and to be able to think of it as not ex- 



PROLEGOMENA LOGICA. 227 

isting; — to fancy that certain positions are condemned by 
the laws of the understanding, when the fact is only that 
their materials have not been given in an intuition ; — to 
suppose that to be rejected by reason which in truth has 
never come in contact with reason at all. 

To examine in detail the prominent instances of the 
above confusion, which are plentifully exhibited by some 
of the so-called philosophers of the present time, would 
require a work of a higher and more controversial charac- 
ter than the present. I shall content myself with selecting 
two examples, one ancient and one modern, as specimens 
of the confident manner in which men of all ages, and 
under all religious systems, have been prone to dogma- 
tize upon the highest matters of speculation, upon no 
better basis than the absence of all materials for speculat- 
ing at all. 

Aristotle's well-known argument, to prove that the hap- 
piness of the gods consists in contemplation, is based on 
the ground that we cannot attribute to them moral attri- 
butes in the only way in which such attributes come within 
the sphere of human consciousness, viz., under the limita- 
tions and imperfections consequent upon human passion 
and human error. What scope, he asks, can there be for 
fortitude, where there is no pain to undergo ; or for tem- 
perance, where there are no evil desires to keep in check? 1 
But the reasoning is incomplete. Cotta, in Cicero, pursu- 
ing the same principle to its ultimate consequences, shows 
clearly that we must equally deny of the Deity the pos- 
session of any intellectual as well as of any moral quality. 
What is the object of reason and intelligence but to gain 
a knowledge of that which is obscure ? What is the pur- 
pose of contemplation but to gain a closer insight into 

i Eth. Nic. x. 8. 



228 PROLEGOMENA LOGICA. 

the nature of the things contemplated ? Intellectual at- 
tainments have the same relation to human ignorance that 
moral virtues have to human frailty. 1 

The error of both these reasonings is the same : it con- 
sists in mistaking a psychological deficiency for a logical 
impossibility. To determine in thought that certain at- 
tributes cannot exist in any being except under given con- 
ditions of manifestation, it would be necessary that we 
should have had personal experience of the abrogation of 
those conditions, and of the absolute destruction of the 
attributes in consequence. But such an experience in the 
present case is, ex hypothesi, impossible ; the conditions 
being those to which the universal human consciousness is 
subject. To pronounce how consciousness exists in beings 
of a different nature from ourselves, it would be necessary 
that we should be capable of possessing their nature and 
faculties, as well as our own, and of comparing the two 
together by the aid of a third power independent of 
either. To pronounce that certain modes of consciousness 
cannot exist save as they exist to us, it is necessary that 
we should have personally tried every other possible rela- 
tion of modes of consciousness to a conscious subject. 
Until human experience has extended thus far, to limit the 
province of faith by that of reason, — to say that what we 
cannot compass in thought we may not believe as existing, 
— is to pass from criticism to dogmatism, a dogmatism rest- 
ing its claims to dictation on a complete ignorance of the 
matter in which it dictates. 

The modern Atheism of the German philosopher Feuer- 
bach is based on a similar confusion. It assumes that the 
measure of what man is to believe is to be determined by 
what he can grasp' in an act of j:>ositive thought ; in other 

1 Cicero, De Natura Veorum, iii. 15. 



PROLEGOMENA LOGICA. 229 

words, that the mere absence of the necessary data for 
thinking at all is tantamount to a logical determination of 
the non-existence of a corresponding object. God, accord- 
ing to this system, is but humanity deified in its intel- 
lectual, or moral, or physical attributes, according to the 
Varying condition, characters, and wants of this or that 
people ; but in all, according to one form or another of 
Anthropomorphism. 

Falsehood is only dangerous from its possessing a certain 
portion of a mutilated truth. The one element of truth 
which underlies the Atheism of the Essence of ReUgion^- 
is the fact, that finite thought can only be positively exer- 
cised on finite objects. Thought, on its positive side, is 
ultimately tested by the individualization of concepts. 
To effect this, they must be referred to the representative 
image of some actual state of consciousness, — sensation, 
volition, affection, etc. In attempting to grasp the Deity 
as an object of positive thought, to speculate beyond 
what is revealed to us of the divine attributes as mani- 
fested in relation and accommodation to human faculties, 
man can only bring God down to his own level, and exer- 
cise his reason on those analogous attributes of which he 
has had experience in his personal consciousness. The 
error consists in overlooking the religious feelings and 
affections, as a distinct class of psychological facts, co- 
ordinate with, not subordinate to, the thinking faculty. 
The history of mankind in general, as well as the con- 
sciousness of each individual, alike testify that religion is 
not a function of thought ; and that the attempt to make 

1 With this work, and others of the same author, I am acquainted 
through the French translation by M. Ewerbeck, entitled, Qu'est-ce que la 
Religion d'apres la nouveUe philosopMe Allemande. 

20 



230 PROLEGOMENA LOGICA. 

it so, if consistently carried out, necessarily leads, firstly 
to Anthropomorphism, and ultimately to Atheism. 

The incompetency of such reasoning to prove its con- 
clusion is manifest from the fact, that the mental phenom- 
ena on which alone it rests, must, from the nature of the 
case, be precisely the same, whether that conclusion be 
true or false. If human thought is subject to laws and 
limitations, formal and material, the mode and the sphere 
of positive thinking must be such as those laws and limi- 
tations require, whether there exist objects beyond it or 
not. But the hypothesis, indispensable to the rationalist, 
that the sphere of thought and that of being are coexten- 
sive, fails altogether to account for the phenomenon of 
negative thinking ; to explain, that is, how it can be that 
man, in the exercise of thought, ever finds himself encom- 
passed with conditions and restrictions, which he is ever 
striving to pass, and ever failing in the effort ; that he ever 
feels himself in the presence of yearnings unsatisfied and 
doubts unsolved ; — yearnings which countless accessions 
to the domain of thought have left as vague and restless 
as before ; — doubts which centuries of speculation have 
made no progress toward answering. These and such like 
humiliating truths, altogether inexplicable on the arrogant 
assumption of a human God contemplating the products 
of his creative intellect, 1 are the natural and necessary fea- 
tures of our position, if we believe that man, as individual 



1 "Ueber die Natur philosophiren," says Schelling, "heisst die Natur 
schafFen." 

" Die Logik," says Hegel, " zeigt die Erhebung der Idee zu der Stufe 
von daraus sie die Schopferin der Natur wird." In the same spirit, Logic 
is declared to be, " Die Darstcllung Gottes, wie er in seinem ewigen Wesen 
vor der Erschaffung der Natur und eines endlicben Geistes ist." 

The mock thunder of Salmoneus was modesty itself to this. 



PROLEGOMENA LOGTCA. 231 

or as species, is but a lower intelligence in the midst of 
the works of a higher; a being of finite intuitions, sur- 
rounded by partial indications of the Unlimited, of finite 
thought, contemplating partial revelations of the Incom- 
prehensible. 



CHAPTER IX. 

OF LOGIC AS RELATED TO OTHER MENTAL SCIENCES. 

A division was early established in philosophy between 
the Logica docens and the Logica uteris ; the one con- 
cerned with the pure laws and forms of thought, the other 
with the application of thought to this or that object- 
matter. The relations of the latter it is not my present 
purpose to examine. Every art or science, in so far as it 
contains reasonings on its own special objects, may be re- 
garded as furnishing an instance of the Logica uteris; 
and in this point of view Logic has no special affinity with 
one branch of knowledge rather than another. But in 
relation to the Logica docens, there are three branches of 
science, real or apparent, which, from community of object 
and method, as well as from historical connection, demand 
a more special consideration. 

The three sciences in question are Grammar, Psychology, 
and Metaphysics. Rhetoric, from an association with Logic 
and Grammar in the mediaeval Trivium, might also be 
thought to have a special claim on our attention. But, in 
truth, Rhetoric is connected by community of object-matter 
rather with the art of Dialectic, as exhibited in the Topics 
of Aristotle and the Probable Syllogisms of the Scholastic 
Logic, than with the formal science as treated of in the 
present work. Its relation to the latter is only by way of 
application, inasmuch as logical forms may be applied in 



PROLEGOMENA LOGICA. 233 

rhetorical exercises ; a relation which reduces it to a level 
with any other employment of the Logica uteris. With 
Psychology, indeed, its connection is far more intimate, 
but on the opposite side from that by which the same sci- 
ence is related to Logic. Logic, as the science of the laws 
and products of the understanding, is related to Psychology 
through the medium of the speculative and discursive fac- 
ulties. Rhetoric, as concerned with the movement of the 
will, is related on the side of the emotional and practical 
faculties, and is thus correctly described by Aristotle as an 
offshoot of Dialectic and Moral Philosophy. 

On the other hand, Psychology, Metaphysics, and Gram- 
mar, are intimately connected with the faculties, the laws, 
and the instruments of the universal process of thought, — 
a connection which has been recognized, with more or less 
clearness, from the origin of Logic to the present time. 
The Categories, from the days of Aristotle downwards, 
have been disputed ground between Logic and Metaphys- 
ics, and are treated of by the Stagirite himself in connec- 
tion with both sciences. The treatise Trepl ep/^i/eta?, whose 
title, sorely misnomered by various translators, might be 
adequately expressed in English by, " Of Language as the 
interpretation of Thought," 1 is, in the early portion, devoted 
to grammatical definitions and distinctions. Psychology 
also, though less prominently introduced, claims her share 
in the multifarious matter of the Organon ; in the account 
of the processes of sensation, memory, and experience, as 
subsidiary to induction. 

Were we indeed to start from the whole Organon of 

1 For various interpretations of Interpretation, see M. St. Hilaire, De la 
Logique d'Aristote, p. i. eh. 10. The version given in the text corresponds 
to that by Isidore of Seville : " Omnis elocutio concept® rei interpres est : 
inde perihermeniam nominant quam interpretationem nos appellamus." 

20* 



234 PROLEGOMENA LOGICA. 

Aristotle, as a uniform treatise on a single subject, it 
would be difficult to accommodate its contents to any- 
modern classification of the mental sciences. But it may 
fairly be questioned whether even the authority of the 
philosopher himself can be adduced in support of such a 
proceeding. While we cannot help admitting, with Sir 
William Hamilton, 1 that the incorrect notions which have 
prevailed, and still prevail, in regard to the nature and 
province of Logic, are mainly to be attributed to the au- 
thority of the father of the science, it may be doubted how 
far that authority has been put to a legitimate use by his 
followers. The same eminent critic to whom we have 
just referred has observed, in another place, that there is 
required for the metaphysician not less imagination than 
for the poet ; that it may, in fact, be doubted whether 
Homer or Aristotle possessed this faculty in greater vigor. 2 
The two authors here placed in juxtaposition may be com- 
pared in more respects than that of their mental powers. 
The influence of Homer in Poetry has been similar to that 
of Aristotle in Philosophy ; yet, while, from the Father of 
Criticism to the present day, there has never been wanting 
a champion to maintain against all impugners the unity of 
design of the Iliad, and its exact relation to a beginning, a 
middle, and an end, the primary argument of this " one 
entire and perfect chrysolite" has been almost as much 
disputed among critics as the question of the definition of 
Logic. Different portions of the poem have been pro- 
nounced genuine or spurious, according to this or that 
conception of the poet's design ; and, finally, it has even 
been maintained that the model of all succeeding Epics is 
little more than a fortuitous concourse of atoms, the frag- 

1 Discussions, p. 141. 2 BeioVs Works, p. 99. 



PROLEGOMENA LOGICA. 235 

ments of distinct rhapsodists. The Organon of Aristotle 
has had a similar fate. Various have been the conjectures 
concerning its design and method. Portions have been at 
different times regarded as logical, as grammatical, as meta- 
physical ; nor have there been wanting critics to deny the 
genuineness of this or that part. The parallel might be 
carried further. The different portions of the Iliad are 
said to have been collected and arranged in the time of 
Pisistratus, about three hundred and forty years after the 
date assigned by Herodotus (rightly or wrongly) to the 
birth of the poet ; and the writings of Aristotle are gener- 
ally supposed to have received their present form and ar- 
rangement at the hands of Andronicus of Rhodes, a philos- 
opher who flourished about three centuries later than the 
Stagirite. I am not indeed aware that any critic has been 
bold enough to maintain a thoroughly Wolfian hypothesis 
of the origin of the Organon ; and yet there are not want- 
ing grounds on which a not very different theory might be 
supported ; not indeed as regards the authorship, but cer- 
tainly as regards the unity of design of the work. The 
title by which the collected treatises are known is undoubt- 
edly of recent origin ; it is not found in Aristotle himself, 
nor in any of his earlier commentators ; and, as far as ex- 
isting evidence can determine, it appears not to have been 
in common use before the fifteenth century. 1 The several 
treatises themselves are invariably mentioned by their au- 
thor as distinct works under distinct titles ; and even after 
the time of Andronicus, commentaries were generally writ- 
ten, not on the Organon as a whole, but separately on its 
constituent parts. If from the books we turn to the mat- 
ters of which they treat, the result is the same. Logic, as 
the name of an Art or Science, does not once occur in the 

1 St. Hilaire, De la Logique cV Aristote, vol. i. p. 19. 



236 PROLEGOMENA LOGICA. 

writings of Aristotle; and the cognate adjective and adverb 
are used in a peculiar and much more restricted sense than 
that which has subsequently been given to them. The 
names sanctioned by the philosopher himself, such as 
Analytic and Dialectic, are commensurate with portions 
only of the Organon; the division of Philosophy into 
Logic, Physics, and Ethics, adopted by the Stoics, and 
sometimes attributed (on questionable grounds) to Plato, 
receives no sanction from the Stagirite ; indeed, he adopts 
a classification in many respects at variance with it, dis- 
tinguishing theoretical philosophy from practical and pro- 
ductive, and dividing the first into three branches. Physics, 
Mathematics, and Theology. 1 

Leaving, then, altogether the question of authority, and 
adopting the formal view of Logic taken in the preceding 
pages as the only one which j)romises to secure for the 
science what it has so long needed, an exact definition and 
a determined field of inquiry, I shall proceed to examine 
the relation in which Logic, as thus exhibited, stands to- 
wards the cognate sciences of Psychology, Grammar, and 
Metaphysics. 

Of Psychology something has already been said in the 
earlier portion of the present Essay. Logic deals with the 
products of the several thinking acts, with concepts, with 
judgments, with reasonings, as, according to certain as- 

1 3Ietaph. v. 1. Mr. Karslake (Aids, p. 10) speaks of the Organon as 
presenting so coherent a system, that the assertion that it contains a few 
only of Aristotle's logical works is doubtful. To me there appears little 
more of coherence than may naturally he expected in distinct writings of 
the same author on any question of Grammar, Analytic, Dialectic, or 
Rhetoric. And, as far as we can conjecture from existing evidence, it is 
most probable that the several books were written in the reverse order of 
that in which they are now arranged. See Burgersdyck, Inst. Log. Pr»f.; 
Fries, System der Logik, p. 15. 



PROLEGOMENA LOGICA. 237 

sumed laws of thinking, they ought to be or not to be. 1 It 
is competent to test the validity of all such products in so 
far as they comply or not with the conditions of pure 
thought, leaving to this or that branch of material science 
to determine how far the same products of thought are 
guaranteed by the testimony of this or that special experi- 
ence. Thus it accepts, as logically valid, all such concepts, 
judgments, and reasonings, as do not, directly or indirectly, 
imply contradictions ; pronouncing them thus far to be 
legitimate as thoughts, that they do not in ultimate analy- 
sis destroy themselves. That they will be also accepted 
upon an appeal to experience, it does not decide ; it only 
recommends them as qualified for further examination. It 
is thus competent to determine the possible existence of a 
class of objects corresponding to a given concept, the 
necessary truth of an analytical, and the possible truth of a 
synthetical judgment, the formal validity of a conclusion 
as necessarily following from certain assumed premises. 
Questions concerning the real existence of this or that class 
of objects, the actual truth of a synthetical judgment, or 
of a conclusion out of relation to its given premises, it 
sends up for judgment to the tribunal of Experience. 

As Experience decides on the relations of any given 
product of thought to the actual phenomena presented by 
this or that object of intuition, so Psychology decides on 
its relations to the actual constitution of the human mind. 
Why it is that the laws of pure thinking extend thus far 
and no further; — what are the mental processes prelim- 

1 " Die gauze reine Logik hat es mit VerMltnissen des Gedachten, des In- 
halts unserer Vorstellungen (obgleich nicht speciell mit diesem Inhalte 
selbst) zu thun; aber iiberall nirgends mit der Thatigkeit des Denkens, nir- 
gends mit der psychologischen, also metapliysiscben, Moglichkeit dessel- 
ben."— Herbart, Fsychologie als Wissenchaft. Th. II. § 119. 



238 PROLEGOMENA LOGICA. 

inary and subsidiary to thought, and the nature of the 
thinking act itself as giving rise to the logical products ; 
— whence arises the phenomenon of illegitimate thinking; 
— the nature and origin of various impediments and errors 
to which thinking and other mental acts are subjected in 
mankind ; — the relation of the several mental acts to one 
or more faculties of mind, and the value of such distinction 
as absolute or relative, implying a notional only, or an 
actual separability ; — in short, all inquiries into the actual 
phenomena of man's mental constitution and their expla- 
nation, form the object-matter of Psychology. 1 

From this it appears that Psychology, as well as Phys- 
ical Science, is, in the widest sense of the term, empirical. 
It inquires, that is to say, what are the actual phenomena 
of the several acts and states of the human mind, and the 
actual laws or conditions on which they depend ; and in 
this sense the laws of thought themselves are empirical, 
and within the province of Psychology, inasmuch as it is 
a matter of fact and experience that men do reason accord- 
ing to them. Logic, on the other hand, can in no sense 
be called empirical, inasmuch as the actual constitution, 
whether of the world within, or of the world without, is 
assumed indeed and implied in its researches, but in no 
respect described or investigated. We are not to ascer- 
tain, as a matter of fact, that men do reason in this or that 
form, as governed by this or that law ; but, on the assump- 
tion of certain laws, we are to determine a priori the forms 
which legitimate thinking ought to exhibit, whether man- 
kind in general do comply with them or not. 2 Logic is 

1 Much of this is distinguished by Kant as Applied Logic, which however 
he allows to be more properly referred to Psychology. 

2 Kant, Logik, Einleitung II. 4; Drobisch, Neue Darstellung der Logik, 
h 9. 



PROLEGOMENA LOGICA. 239 

indeed ultimately to be referred to the test of experience ; 
but only in respect of its conformity with facts without 
its province, not in respect of the coherence of its parts 
within. So far as it implies that, as a matter of fact, men 
do reason in syllogisms, so far its pretensions maybe tested 
by reference to the empirical truths of Psychology. So 
far as it asserts that the legitimate forms of the syllogism 
are such and such, it is singly deductive a priori, and 
necessarily valid for any class of thinking beings whose 
laws are such as it presupposes. An empirical science may 
contain much partial truth, though omitting many impor- 
tant phenomena and erroneously accounting for many 
which it recognizes. It offers much, therefore, for enlarged 
experience gradually to supply and correct. An a priori 
Science, like Logic, is tested by experience only with refer- 
ence to its fundamental hypotheses. If these are accepted, 
they carry with them the whole superstructure of details. 
If these are rejected, every portion of the science falls to 
the ground along with them. 

But though Logic and Psychology have thus each their 
respective provinces and methods, it cannot be too often 
repeated that neither can be taught as a science, efficiently 
and satisfactorily, unless in connection with the other. We 
may learn by rote a multitude of logical rules, and fondly 
imagine that we are acquiring an art which will enable us 
to think ; — a course of Logic being in fact about as ne- 
cessary for making men thinkers as a course of Ethical 
Philosophy for making them honest, or a course of Optics 
for enabling them to see. Or we may analyze in dictione 
and extra dictionem all sorts of imaginary fallacies pro- 
pounded by imaginary sophists, and dream that we are 
forging an impenetrable panoply against all the deceits 
of the world; — as if we could bind men down in heavy 



240 PROLEGOMENA LOGICA. 

securities to lie and cheat by rule, in order that they may 
be detected in due course of art. Or we may draw up 
syllogisms in orthodox mood and figure, and babble about 
Laws of Thought, and never dream of asking what is the 
nature of Thought as a process, and with what elements 
does it combine in the actual formation of this or that 
compound. Or, on the other hand, starting from confused 
or erroneous notions of the nature and powers of the hu- 
man mind, we may blame Logic for not accomplishing what 
no science can accomplish, and deem its whole contents a 
tissue of jargon and imposture, because it is neither able to 
open a Royal Road to the Encyclopaedia, nor to convert 
natural folly into supernatural wisdom. It may safely be 
asserted that nine-tenths of the mistaken judgments to 
which Logic has been subjected on the part of friends and 
adversaries, unreasonable eulogy on the one hand, equally 
unreasonable abuse or contempt on the other, have been 
owing to its treatment out of relation to Psychology, — to 
its having been expounded and studied without any pre- 
liminary attempt to ascertain what are the nature and 
limits of the thinking faculty, and what character its laws 
and products ought to exhibit in conformity with the con- 
stitution of the human mind. 

With Grammar Logic is connected through the medium 
of the universal instrument of thought, Language. The 
practical necessity of this instrument for the formation as 
well as for the communication of thought, has been noticed 
already ; it remains to inquire in what different ways this 
their common object is dealt with by Logic and Grammar 
respectively. Universal Grammar, with which alone we 
are concerned (the history and idiomatic peculiarities of 
special languages being obviously unconnected with gen- 
eral Logic), has been happily defined as " The science of the 



PROLEGOMENA LOGICA. 241 

relations which the constituent parts of speech bear to 
each other in significant combination." 1 It is thus con- 
cerned with Language primarily and essentially ; Logic, 
secondarily and accidentally. The former has given certain 
articulate sounds, to find their relation to certain supposed 
counterparts in thought. The latter has given to deter- 
mine the necessary relations of concepts to each other; 
but in so doing it is compelled secondarily to exhibit the 
corresponding relations of the sounds by which concepts 
are represented. 

The two sciences differ also in the extent of their prov- 
inces. Logic considers language simply as the instrument 
and representative of thought. Grammar will include its 
relation to intuitions and emotions, and every state of con- 
sciousness which finds its expression in speech. 2 Logic 
considers language only in so far as it is indispensable to 
thought, and accordingly analyzes speech only to that 
point at which it is representative of the simplest element 
of thought, the concept. Any parts into which a concept 
may be divided, which are not themselves concepts, are 
beyond its province, as not being representative of a com- 
plete thought, nor competent instruments alone for the 
performance of an act of thinking. Hence all syncate- 
gorematic words, as not being per se significant, are not 
recognized by Logic. 

In Grammar the unit of thought is a judgment, both 
terms being necessarily represented by words. Hence the 
unit of speech in Grammar is a proposition ; the office of 
the subordinate parts of speech being to limit or connect 

1 Sir John Stoddart, Philosophy of Language, pt. i. p. 21. Universal 
Grammar is properly a science, particular Grammar an art, as is observed 
by Du Marsais, Encyclopedic, Art. Grammaire, p. 842. 

2 See Harris, Hermes, ch. iii. 

21 



242 PROLEGOMENA LOGICA. 

the primary parts as subjects or predicates of a given 
assertion. 1 Such connections and limitations may be 
more conveniently effected by the invention of words ex- 
pressive of relations between concepts, than by the use of 
distinct signs for every new concept resulting from such 
relations ; this, however, is one of the luxuries only, not 
one of the necessaries of language, and, as such, is not 
noticed by Logic. Viewed simply as an element of 
thought, it is indifferent^ whether the same concept be 
expressed by a combination of substantive and adjective, 
as in the English "four-footed beast," or the German 
" vierfiissiges Thier," by the interposition of a preposition, 
as in the French " bete a quatre pieds," or by a single sub- 
stantive, such as the classical equivalent, " quadruped." 

In Logic the unit" of thought is also a judgment, but 
not one which requires a verbal representative of both its 
constituent parts. Conception, the simplest act of thought, 
consists in the referring a given concept to possible objects 
as imagined. Here there is, in the psychological sense 
of the term, a judgment ; i. e., a consciousness of the pres- 
ence of the objects in thought ; but that consciousness 
does not form an additional concept, nor require as its 
necessary exponent a second verbal sign. Hence the unit 
of speech in Logic is a term ; such being a sufficient verbal 
instrument for the performance of the first and the simplest 
act of thought. 

With reference to the second operation of thought, 
judgment, wherein the two sciences come most nearly into 
contact, the following distinction is important. Grammar 
considers words objectively, as signs of things. Hence 

1 For a further illustration of this doctrine, not universally held by Gram- 
marians, the reader is referred to an article by the present author, on the 
Philosophy of Language, in the North British Review, No. 27. 



PROLEGOMENA LOGICA. 243 

the distinction of tenses, according as the remote or repre- 
sented object is considered as contemporaneous with, or 
distant in time from, the speaker. Logic considers words 
subjectively, as signs of thoughts. Hence the only logical 
tense is the present, the immediate or presented objects 
being necessarily contemporaneous with the act of con- 
sciousness by which they are now thought in conjunction. 1 
It is sometimes said that Logic recognizes two only of 
the grammatical parts of speech, the noun and the verb, 
forming the two terms of the proposition with and with- 
out time. 2 It would be more correct to say that Logic, 
viewing language in a different light from Grammar, and 
analyzing on a different principle, does not recognize 
the grammatical parts of speech at all. The simplest ele- 
ments of a complete assertion in Grammar are the noun 
and the verb ; 3 the latter being a combination of attribute 
and assertion. Hence the grammatical type of a proposi- 
tion is that distinguished in scholastic language as secundi 
adjacentis ; and to this form all varieties produced by 

i See p. 71. 

2 " Grammatici enim, considerantes vocum figuras, octo orationis partes 
annumerant. Philosophi vei'O, quorum omnis de nomine verboque trac- 
tatus in significatione est constituta, duas tantum orationis partes esse 
docuerunt: quicquid plenam significationem tenet, siquidem sine tempore 
signiflcat, nomen vocantes; verbum vero, si cum tempore." — Boethius, 
Int. ad Syll. p. 561. " Et sciendum est quod Dialecticus solum ponit duas 
partes orationis, scilicet nomen et verbum. Alias autem omnes appellat 
syncategorematicas, id est consignificativas." — Petr. Hisp. Sum. Log. Tr. i. 
Here, as in the De Interpretatione of Aristotle, the type of the logical prop- 
osition is the form distinguished as secundi adjacentis, the verb being 
neither the copula alone, nor the predicate alone, but the combination of 
the two, however expressed. A neglect of this has misled many commen- 
tators and critics on Aristotle, from Ammonius to the present day. 

3 " In all languages there are only two sorts of words which are necessary 
for the communication of our thoughts, the noun and the verb." — Tooke, 
Div. of Purley, ch. 3. 



244 PROLEGOMENA LOGIC A. 

the accidents of particular languages must, in Universal 
Grammar, be virtually reduced. 1 In Logic, on the other 
hand, for the purposes of opposition and conversion, as 
well as from the necessity of assigning a quantity to both 
terms of the proposition, the type is required to be of the 
form tertii adjacentis ; the subject and predicate being 
regarded as two given concepts, the objects of which are 
identified or distinguished by means of the copula. Hence, 
in every case in which the proposition is exhibited in its 
logical form, the grammatical verb" will correspond not to 
any single word in the proposition, but to a combination 
formed of the copula and the quantified predicate, — to 
all, in short, that is asserted of the subject. The predicate 
concept may thus, in different points of view, answer to 
two distinct grammatical relations. Taken by itself, it is 
a noun, identified in certain respects with another noun as 
the subject. Taken in its predicate character, it forms a 
portion of the verb, the remainder being supplied by the 
copula. Those logicians who maintain the copula to be 
the logical verb, confound the accidents of particular lan- 
guages with the essentials of language in general as a 
sign of thought. With them the verb is determined solely 
by the subordinate feature of its personal inflection, not 
by the primary characteristic of its signification. 

With regard to the relation of Logic to Metaphysics, 
some preliminary verbal explanation is necessary, owing to 

1 Hence it follows that the copula is, grammatically speaking, no verb 
at all. It fulfils none of the functions of that part of speech; for it implies 
no attribute, and cannot, when united to a subject, form a complete asser- 
tion. In such a sentence as " The meadows are white with frost," the true 
verb is not the copula, but the copula with the adjective, are white, as may 
be seen by substituting the Latin, " prata canis dlbicant pruinis." Whether 
this can be expressed in one word or not, is an accident of this or that lan- 
guage, and is beyond the province of Universal Grammar. 



PROLEGOMENA LOGICA. 245 

the various senses in which the latter term has been used. 
Among modern philosophers, empirical psychology, which 
the ancients regarded as a branch of physics, 1 is frequently 
classified as metaphysical. Thus the contributions of 
Reid and Stewart to the inductive science of the human 
mind are not unfrequently spoken of as Scotch Meta- 
physics ; a nomenclature which the latter of these philoso- 
phers has in some degree sanctioned by his own writings. 2 
Such a classification is, however, inconsistent with the fun- 
damental doctrines of the Scottish School. It has been 
before observed that one of their leading principles is, that, 
in the investigation of mind as well as of matter, phenom- 
ena alone are the legitimate objects of science ; the sub- 
stance and essential nature of both being beyond the reach 
of human faculties. Whereas Metaphysics has from the 
earliest days been distinguished as the Science of Being as 
Being, in opposition to all inquiries into the phenomena 
exhibited by this or that class of objects. 3 How far such 
a problem is capable of solution is another question ; but 
the mere propounding of it implies an object totally dis- 
tinct from that of an inquiry into the faculties and laws 
of the human mind. 

The object of the older Metaphysics has been distin- 

1 See Hamilton on Reid, p. 216. 

2 For instance : " Nothing contributes so much to form this talent as 
the study of Metaphysics; not the absurd Metaphysics of the Schools, 
but that study which has the operations of the mind for its object." — Ele- 
ments, vol. i. ch. 2. In other places Stewart has noticed this phraseology 
as a loose use of language, and has attempted to account for it. But the 
term ought never to have been used at all. 

3 Arist. Metaph. iii. 1. *E<ttiv 4iri<TTr)firi tis $7 becopei rb %v y tu Kal to 
tovtw inrdpxovra Kcfo' avrS. The name Metaphysics is of much later 
date, but its object has always been regarded as identical with that 
distinguished by Aristotle as First Philosophy, or Theology. Cf. Wolf, 
Ontoloyia, § 1. 

21* 



246 PROLEGOMENA LOGICA. 

guished in all ages as the one and the real, in opposition 
to the many and the apparent. 1 Matter, for example, as 
perceived by the senses, is a combination of distinct and 
heterogeneous qualities, discernible, some by sight, some 
by smell, some by touch, some by hearing. What is the 
thing itself, the subject and owner of these several qual- 
ities, and yet not identical with any one of them ? What 
is it by virtue of which these several attributes constitute 
or belong to one and the same thing ? Mind, in like man- 
ner, presents to consciousness so many distinct states and 
operations and feelings. What is the nature of that one 
mind, of which all these are so many modifications? The 
inquiry may be carried higher still. Can we attain to any 
single conception of Being in general, to which both Mind 
and Matter are subordinate, and from which the essence 
of each may be deduced? 2 

Ontology, or Metaphysics proper, as thus explained, 
may be treated in two different methods, according as its 
exponent is a believer in to 6v or in to. 6Vra, in one or in 
many fundamental principles of things. In the former, all 
objects whatever are regarded as phenomenal modifica- 
tions of one and the same Substance, or as self-determined 
effects of one and the same Cause. The necessary result 
of this method is to reduce all metaphysical philosophy 
to a Rational Theology, the one Substance or Cause 
being identified with the Absolute, or the Deity. Accord- 
ing to the latter method, which professes to treat of dif- 
ferent classes of Beings independently, Metaphysics will 
contain three coordinate branches of inquiry: Rational 
Cosmology, Rational Psychology, and Rational Theology. 3 

/ 

1 Arist. Metaph. iii. 2. 

2 Wolf, Phil Bat. Disc. Prod. § 73; Herbait, Allgemeine Metaphysik, § 27. 

3 Herbart, Lehrbuch zur Philosophie, § 7; Allgemeine Metaphysik, § 31. 
Anm. 



PROLEGOMENA LOGICA. 247 

The first aims at a knowledge of the real essence, as dis- 
tinguished from the phenomena, of the material world; 
the second discusses the nature and origin, as distinguished 
from the faculties and affections, of the human soul, and 
of other finite spirits; 1 the third aspires to comprehend 
God Himself, as cognizable a priori in his essential nature, 
apart from the indirect and relative indications furnished 
by his works, as in Natural Theology, or by his word, as 
in Revealed Religion. These three objects of metaphysi- 
cal inquiry — God, the World, the Mind — correspond to 
Kant's three Ideas of the Pure Reason; and the object 
of his Critique is to show that, in relation to all three, 
the attainment of a system of speculative philosophy is 
impossible. 

The former of these methods is the bolder and the more 
consequent ; and, moreover, the only one which can be 
consistently followed by those who believe in the possi- 
bility of a Philosophy of the Absolute. For, a plurality 
of real objects being once admitted as the highest reach 
attainable by human faculties, these must necessarily be 
regarded as related to, and limited by, each other. Ac- 
cordingly, this method has been followed by the hardiest 
and most consistent reasoners on metaphysical questions ; 
by Spinoza, under the older form of Speculation, and by 
Hegel, after the Kantian revolution. But thus treated, 
metaphysical speculation necessarily leads to Pantheism ; 

1 " Man findet hier die Trenmmg der empirischen von der rationalen 
Psych ologie ; die erste durchlaiift die einzelnen sogenannten Seelenvermo- 
gen; die andre spricht iiber Natur und Ursprung der Seele, iiber Unster- 
blichkeit, Zustand nach.dem Tode, Unterschied zwischen den Seelen der 
Menschen, der Thiere, und den hoheren Geistern." — Herbart, Allgemeine 
Metaphysik, § 29. For a curious account of theories and theorists in 
rational psychology, see Burton, Anatomy of Melancholy, P. i. sect. i. 
Mem. 2, Subs. 9. 



248 PROLEGOMENA LOGICA. 

and Pantheism, at this elevation, is for all religious pur- 
poses equivalent to Atheism. 1 The method is thus con- 
demned by its results ; and the condemnation will not be 
retracted upon a psychological examination of its princi- 
ples. Its fundamental conception is not thought, but its 
negation. The Thought which is identified with Being in 
general, is not my thought, nor any form of consciousness 
which I can personally realize. 2 My whole consciousness 
is subject to the conditions of limitation and relation of 
subject and object. A system which commences by deny- 
ing this relation, starts with an assumption concerning the 
possible character of an intelligence other than human, and 
consequently incapable of verification by any human being. 
Yet the system is the product of a human thinker, and 
addressed to human disciples. 

The second method of metaphysical inquiry is less pre- 
sumptuous, though perhaps also less consistent. It starts 
with the assumption of a plurality of Beings, thus virtu- 
ally abandoning the Philosophy of the Absolute. This 
plurality is primarily manifest in the contrast between the 
Subject and the Object of Consciousness, between self and 

1 It has of late been a favorite criticism of Spinoza to say, with Hegel, 
that his system is not Atheism, but Acosmism; and this is true in a specu- 
lative point of view. But if I allow of no God distinct from the aggregate 
of the Universe, myself included, what object have I of worship? Or if, 
according to the later manifestation of Pantheism, the Divine Mind is but 
the sum total of every finite consciousness, my own included, what reli- 
gious relation between God and man is compatible with the theory? And, 
accordingly, the Pantheism of Hegel has found its natural development in 
the Atheism of Feuerbach. 

2 This is expressly stated by an eminent disciple of Hegel, who professes 
to discover in Aristotle's Metaphysics an anticipation of Hegelianism: 
" La pensee que nous venons de decrire est la pense'e absolue. II ne s'agit 
pas ici de la pensee subjective, qui est uue fonction psychologique restreinte 
a l'ame humaine." — Michelet, Examen dela Metaphysique d'Aristote, p. 216. 



PROLEGOMENA LOGICA. 249 

not-self, as related to and limiting each other. But the 
consciousness of the relative and limited suggests by con- 
trast the idea of the absolute and unlimited ; and thus 
gives rise to three distinct branches of metaphysical spec- 
ulation : the ego being identified with the substance of the 
human soul, as distinguished from its phenomenal modes; 
the non-ego being identified with the reality which under- 
lies the phenomena of the sensible world ; and the absolute 
or unconditioned with the Deity. 1 Of the last of these 
three branches, that commonly known as Rational Theol- 
ogy, which endeavors from the conception of God as an 
absolutely perfect Being to deduce the necessary attributes 
of the Divine Nature, I shall say nothing in this place. 
The question of the relation of the human mind to reli- 
gious intuitions is one of the most delicate and the most 
difficult in Psychology, and to treat it adequately would 
require a separate volume. On the two latter branches of 
Metaphysics, which Kant regarded as equally unattainable 
with the first, something has been said in a former chapter. 
It was the opinion of Kant, as well as of Reid and Stewart, 
that the subject of mental as well as of bodily attributes is 
not an immediate object of consciousness; in other words, 
that in mind, as well as in body, Substance and Unity 
are not presented, but represented. Those who accept this 
doctrine are only consistent in regarding metaphysical in- 
quiry in all its branches as a delusion. But a philosophical 
examination is incomplete unless it not only points out 
the truth, but likewise explains the cause of error. The 
weak point of the above doctrine is, that it fails in 

1 These three branches of Metaphysics have been considered somewhat 
more in detail, by the present author, in the Article Metaphysics, in the 
eighth edition of the Encyclopaedia Britannica, vol. xiv. pp. G04 sqq., 615 sqq. 



250 PROLEGOMENA LOGICA. 

explaining, on psychological grounds, how the supposed 
delusion originated. Experience furnishes, if not the 
cause, at least the occasion of every object of our cogni- 
tion ; and, unless upon the supposition that a knowledge 
of Unity and Substance is immediately given in one phase 
at least of consciousness, it is impossible to account for its 
invention in any. The multifarious phenomena of in- 
ternal as well as of external sense, present, on the opposite 
hypothesis, nothing in any respect analogous to the sub- 
stance to which they are attributed, — nothing that can 
operate in any way even as the occasional cause from 
which the existence of such a substance could be suggested. 
Metaphysical philosophy may contain much that is ground- 
less, much that is deceptive ; but the whole analogy of 
deception and hypothesis in other branches of speculation 
leads to the conviction that it can only arise from rashly 
transferring to new relations ideas which are given in some 
relation or other. 

Instead, therefore, of considering the whole of Meta- 
physics to be based on a delusion, and its ultimate destiny 
to be utter extinction, we shall probably come nearer to 
the truth if we regard its unsound portions as based on a 
perverted intuition, and anticipate that it will be finally 
absorbed in that science to which the intuition in its orig- 
inal relation properly belongs. If, for example, it should 
ultimately be made manifest that to the material world we 
have no relation except through the various phenomena 
of sense, but that in the mental world Self, as well as the 
phenomena of self, is an immediate presentation of con- 
sciousness, it will follow that in the former we have no 
ground for maintaining the existence of things other than 
the phenomena presented; and that consequently, in this 
department, Ontology, as distinct from Phenomenology, 



PROLEGOMENA LOGICA. 251 

is occupied solely with chimeras of our own invention : 
whereas, Psychology, being called upon to extend its 
inquiries from the phenomena of self to that of which 
they are phenomena, will legitimately include the remain- 
ing portion of those problems which have hitherto been 
appropriated to Metaphysics. 

But this question cannot be discussed here. My present 
concern is only with the relation supposed to exist between 
Metaphysics, as above described, and Logic. In the earlier 
form of Metaphysics, which prevailed from Aristotle to 
Kant, an intimate connection was supposed to exist be- 
tween the two sciences. The Principles of Contradiction 
and Excluded Middle, which have been exhibited in a 
former chapter as Laws of Thought, are found in the met- 
aphysical as well as in the logical writings of Aristotle; 1 
and the former, together with that of Sufficient Reason, is 
placed by Wolf, the immediate predecessor of Kant, at the 
head of Ontology. 2 But, after the Kantian Critique, this 
association was no longer possible. Kant showed clearly 
that, without synthetical judgments a priori, Metaphysical 
science is impossible ; and this at once put an end to all 
attempts which had hitherto been made to elicit a science 
of Being from the laws of formal thinking, which are the 
foundation of Logic. The two sciences, thus divorced, be- 
come apparently united again in the system of Hegel ; but 
the union is apparent only. For the Hegelian Logic is 

1 For the principle of Contradiction see Arist. Metaph. iii. 3, x. 5; Anal. 
Pr. ii. 2; Anal. Post. i. 11. For that of Excluded Middle, see Metaph. iii. 
7, ix. 4; Anal, Pr. i. 1; Anal. Post. i. 2, ii. 13. They may also be traced 
to Plato. See Phcedo, p. 1*03; Republic, iv. p. 436; Sophist, pp. 250, 252. 
They are given more explicitly in the Second Alcibiades, p. 139; but this 
dialogue is generally considered spurious. 

2 Cf. Wolf, Ontologia, §§ 27, 29, 56, 71, 498. 



252- PROLEGOMENA LOGICA. 

based, not on an acknowledgment, but on a defiance of 
the Laws of Thought. It is a Logic of the Reason, of 
which the fundamental position is, that the Laws of the 
Understanding are applicable to finite objects only, and 
that Thought in relation to the infinite is free from their 
dominion. Logic thus returns, as regards its object, not to 
the Aristotelian Analytic, but to the Platonic Dialectic, as a 
science of the Real and the Absolute; though the method 
pursued is opposed to Plato as much as to Aristotle. 1 On 
the other hand, in proportion as we adhere more closely to 
the formal view of Logic, the separation of that science 
from Metaphysics becomes more complete. An eminent 
advocate of that view, who is far from adopting Kant's 
opinion of the impossibility of Metaphysics, expresses his 
conviction of the very different objects and methods of 
the two sciences, by likening the union of Metaphysics and 
Logic to a lecture on the Integral Calculus and the Rule 
of Three. 2 And there is much truth implied in this some- 
what overstrained comparison. With formal Logic, Meta- 
physics stands rather in opposition than in connection. 
The former is the science of the ultimate laws of the 
thinking subject ; the latter, of the ultimate realities of 
the objects about which we think. 

Metaphysical inquiry, if capable of a successful prose- 
cution, may furnish a criticism or explanation of certain 
forms of thought assumed by Logic ; for a form of thought 
implies a certain relation between given objects, — a re- 
lation which might be further elucidated if the nature of 
objects in general could be satisfactorily determined. Thus 
we have seen that the form of logical judgments and rea- 

1 On the contrast between the methods of Plato and Hegel, see Trendel- 
enburg, JLogische Untersuchungen, i. p. 89. 

2 Herbart, Lehrbuch zur Philosophie, Vorrede zur zweiten Ausgabe. 



PROLEGOMENA LOGICA. 253 

sonings contains by implication those negative notions of 
substance and cause, the investigation of which is the 
special object of metaphysical inquiries. The science of 
Metaphysics, therefore, if it could be constructed on a solid 
basis, would furnish a criticism of those principles which 
are tacitly acknowledged in every mental process. But, 
for the purposes of formal Logic, such a criticism is not 
needed. It is sufficient for that science to accept the prin- 
ciples in the obscure form in which they are acknowledged 
by common thought and common language ; especially as, 
being indifferently implied in sound and unsound thinking, 
they furnish no criterion by which we can distinguish the 
one from the other. 

This view is confirmed by the history of philosophy 
clown to the present time. While Logic, from the days 
of Aristotle, has been in possession of a scientific method 
and a definite contents, whose truth, whatever opinion may 
be entertained of their utility, no critic has succeeded in 
impugning; Metaphysics has, from the same period, been 
equally conspicuous as the changing Proteus of philosophy, 
whose concealed wisdom, sought after by ceaseless efforts 
of strength and countless varieties of artifice, has invaria- 
bly eluded the inquiries of his worshippers. The union 
of the two, so far from contributing to the scientific com- 
pleteness of the former, has only served to mar its beauty 
and simplicity by extralogical details, and to misrepresent 
its true purpose and value by obscure intimations of deeper 
mysteries lying hid beneath its apparent surface. On the 
other hand, in proportion as the true character of Logic 
as a science has become better known and appreciated, it 
has gradually been separated from Metaphysics, and been 
associated with Psychology. As the science of the laws of 
thought, it is absurd to expect that its object and character 

22 



254 PROLEGOMENA LOGICA. 

can be rightly estimated by those who are unacquainted 
with the nature and powers of the understanding itself, — 
with its relation to the cognate faculties and operations of 
the human mind, — with its legitimate province and duties. 
It is only in this connection that we can hope to see Logic 
finally freed from the unsightly excrescences with which 
it has hitherto been deformed, yet still retaining a clearly 
defined portion of valuable scientific truth, and cultivated 
in a spirit of enlightened appreciation and criticism, equally 
removed from the blind veneration of the idolater and the 
blind hostility of the iconoclast. It is only in this connec- 
tion that the boundaries of the two sciences can be clearly 
marked out, and those portions of psychological matter 
and phraseology whose random introduction has contrib- 
uted so much to deface and obscure the pages of logical 
treatises, can become of inestimable value as part and 
parcel of a cognate and complementary, but by no means 
identical study. And if, in this association, it becomes 
necessary to abase considerably the once towering ambi- 
tion of the Art of Arts and Science of Sciences, the loss is 
more than compensated by the substitution of a humbler 
indeed, but more attainable and more serviceable aim, — 
the knowledge of the distinct provinces to be assigned to 
Thought and Experience respectively, of the true value of 
each within its province, and its worse than uselessness 
beyond; — the knowledge of ourselves and our faculties, 
of our true intellectual wealth, the nature of its tenure, 
and the conditions of its lawful increase. By such culti- 
vation alone can we hope to see Logic finally exhibited in 
its true character, and estimated at its true value ; neither 
encumbered with fictitious wealth by a spurious utilitari- 
anism, nor unprofitably buried in the earth of an isolated 
and barren formalism. 



APPENDIX 



APPENDIX 



Note A, p. 84. 

It is much to be regretted that Dr. Whcwcll, who has made good use 
of Kantian principles in many parts of his " Philosophy of the Inductive 
Sciences," has not more accurately observed Kant's distinction between 
the necessary laws under which all men think, and the contingent laws 
under which certain men think of certain things. His neglect of this 
distinction has given a seeming advantage to the empirical arguments 
of his antagonist, Mr. Mill, who is thus enabled apparently to decide the 
question at issue by what is in reality no more than an argumentum ad 
Jiominem. Thus Dr. Whewell says, of certain discoveries of physical laws, 
" So complete has been the victory of truth in most of these instances, 
that at present we can hardly imagine the struggle to have been necessary. 
The very essence of these triumphs is that they lead us to regard the views 
we reject as not only false, but inconceivable." In this relation, it is obvi- 
ous that the inconceivability is, with reference to the human mind, merely 
contingent, and relative to the particular studies of particular men. Before 
the days of Copernicus, men could not conceive the apparent motion of 
the sun on the heliocentric hypothesis : the progress of science has re- 
versed the difficulty; but the progress of science itself is contingent on 
the will of certain men to apply themselves to it. By thus endeavoring 
to exalt inductive laws of matter into a priori laws of mind, Dr. Whewell 
has unintentionally contributed to give an undue plausibility to the oppo- 
site theory, which reduces all laws of mind into the mere associations of 
this or that material experience. 

But, on psychological grounds, it would seem as if the point of separa- 
tion between a priori principles and empirical generalizations ought not to 
be very difficult of determination. The difference is not one of degree, but 
of kind; and the separation between the two classes of truths is such that 
no conceivable progress of science can ever convert the one into the other. 

22* 



258 A P P'E N D I X . 

That which is inconceivable, not accidentally from the peculiar circum- 
stances of certain men, but universally to all, must be so in consequence 
of an original law of the human mind; that which is universally true 
within the field of experience indicates an original law of the material 
world. No transformation of the one into the other is possible, unless the 
progress of science can change mind to matter or matter to mind. It is 
therefore incumbent on the philosopher who would extend mathematical 
certainty to the domain of physical science, to confirm, in every instance, 
his theory by a psychological deduction of his principles, as Kant has 
done in the instances of Space and Time. 

Dr. Whewell lays much stress on clearness and distinctness of conceptions 
as the basis of the axiomatic truths of physical science. But the clear- 
ness or distinctness of any conception can only enable us more accurately 
to unfold the virtual contents of the concept itself; it cannot enable us to 
add a priori any new attribute. In other words, the increased clearness 
and distinctness of a conception may enable us to multiply to any extent 
our analytical judgments, but cannot add a single synthetical one. 
Without something more than this, the philosopher has failed to meet the 
touchstone of the Kantian question : How are synthetical judgments a priori 
possible ? 

The spirit of Dr. Whewell's Philosophy of the Inductive Sciences is 
beyond all praise. In these days of Positivism and Empiricism it is re- 
freshing to find a writer of such vast attainments in the details of physical 
science comprising them under such truly philosophical principles. But 
it is to be regretted that the accuracj^ of his theory has been in some 
instances vitiated by a stumble on the threshold of the Critical Philosophy. 
The distinction laid down by Kant between the synthetical, or, properly, 
geometrical, and the analytical or general axioms, seems to have been 
altogether overlooked. Thus, almost at the outset of the Philosophy of 
the Inductive Sciences, the analytical judgment, " If equals are added to 
equals, the wholes are equal," is given as a condition of the intuition of 
magnitudes ; l and the same oversight runs through the Essay on Math- 
ematical Reasoning, in which he speaks of "self-evident principles, not 
derived in any immediate manner from experiment, but involved in the 
very nature of the conceptions which we must possess, in order to reason 
upon such subjects at all." The very nature of the conceptions, however 
clearly apprehended, can give rise only to analytical judgments. 

And such, I think, may be shown to be the character of all the mechan- 
ical axioms derived from the idea of Force. Of force, apart from the 
conscious exertion of will, we have no positive conception per se; we know 

1 Book ii. ch. ix. 



APPENDIX. 259 

it only by its effects. Of equal forces we have no positive conception 
beyond that of the production of equal effects. To assert, therefore, that 
equal forces will balance each other at the two extremities of a lever, is to 
assert no more than that effects universally equal will be equal in any par- 
ticular case. 1 

But to establish Mechanics as an a priori science upon the idea of force, 
it will be necessary to commence with some axioms at least of a syntheti- 
cal character, analogous to the geometrical principles, " Two straight lines 
cannot enclose a space ;" or, " If a straight line meets two straight lines, so 
as to make the two interior angles on the same side together less than two 
right angles, the two straight lines will meet if produced." 

As a matter of fact, I do not think that Dr. Whewell has hitherto suc- 
ceeded in establishing, in the science of Mechanics, a system of a priori 
synthetical truths derived from the idea of force as distinct from those 
which are mere applications of the mathematical intuitions of time or 
space. But as regards mere hypothetical mechanics, such a system is not 
inconceivable. A more exact psychological analysis of the intuitive fac- 

l We must distinguish between the general theoretical statement of this axiom 
and its practical application to any given object. In Geometry, the axiom, " If 
equals are added to equals the wholes are equal," is a mere analytical judgment 
derived from the principle of Identity; but to ascertain whether two given mag- 
nitudes are equal, is a question of experiment or observation. So in Mechanics, 
the axiom that bodies acting with equal forces to turn a lever in opposite direc- 
tions will retain it in equilibrium, is analytical; and as thus stated, it is unneces- 
sary to add either that the directions of both forces must be perpendicular, or 
the arms of the lever equal. But in any special application of the axiom there 
arises at once the question, How can we ascertain that any two given forces are 
equal as forces acting upon the lever ? If the force, for example, be gravity, and 
two equal weights be suspended, one perpendicularly, the other obliquely, the 
whole weight of the latter does not act to turn the lever in opposition to the 
former, and the hypothesis of the axiom is violated ; the forces not being in 
that relation equal. Or if both are suspended perpendicularly, but at unequal 
distances from the fulcrum, the moments, or forces in relation to the lever, are 
not equal. The axiom, as stated by Dr. Whewell, " If two equal forces act per- 
pendicularly at the extremities of equal arms of a straight line,*' has the appear- 
ance of a synthetical judgment, by comprehending under one formula the mere 
analysis of the notion of equal forces, and the empirical determination of equal- 
ity in any particular instance. If by equal forces is meant forces equal in effect 
on the lever, the axiom, as stated by Dr. Whewell, is tautological ; if the mean- 
ing is, forces equal in their effects in some other situation, the axiom is empirical 
only, and not even universally true. But, except by its effect in some situation 
or other, what test have we of the magnitude of a force? 



260 APPENDIX. 

ulties may possibly establish the existence of other subjective conditions 
of intuition besides those of space and time, and, consequently, of other 
synthetical judgments a priori besides those of Geometry and Arithme- 
tic. 1 But when the same theory comes to be applied, not to hypothetical 
rigid bodies without weight, but to the actual phenomena of natural 
agents, as in the " Demonstration that all matter is heavy," and, verbally 
at least, in speaking of the inconceivability of the pre-Copernican astron- 
omy, we see at once that the boundary is overleaped which separates the 
necessary laws of thought from the generalized phenomena of matter. 
This absolute boundary is sufficiently marked. No matter of fact can, in 
any possible state of human knowledge, be a matter of demonstration. 2 Nay, 
even supposing such a demonstration possible, it would not add one tittle 
to the evidence of the fact, as such, in the eyes of any one but an egoist. 
By him it would be accepted as an additional proof that what are com- 
monly considered as phenomena of the non-ego, are really only modifica- 
tions of the percipient mind, and governed solely by mental laws. But to 
the Realist it would at most only suggest the possibility of a preestablished 
harmony between the laws of mind and matter, — a suggestion which 
would require, in every special case, to be verified by the empirical exam- 
ination of the latter. Mental laws, which alone determine conceivability, 
are primarily operative only on mental objects, and are applicable to 
external things only on the hypothesis of their conformity. This hypoth- 
esis can only be verified empirically. That every triangle, for example, 
has its angles equal to two right angles, is strictly true only of the perfect 
triangle as contemplated by the mind. That this bit of paper lying before 
me has its angles equal to two right angles, is only true on the supposition 
of its being a perfect triangle; and the truth of this supposition, in any 
possible state of perfection of human senses and instruments, can only be 
determined empirically. It remains always conceivable that there may be 
an error in the measurement, and that the paper may not have exactly 
two right angles. The probability of such an error may be diminished to 
any degree, according to the perfection of our means of measurement; 
but no approximation of this kind can ever become absolute certainty. 

It is not without some hesitation that I have ventured thus far to crit- 
icize a work which I believe to be, in its whole spirit and conception, by 
far the most valuable contribution of modern times to the philosophy of 
the physical sciences. To those who would survey this branch of knowl- 

1 Personality may perhaps be specified as another condition of this kind, and 
the d priori principles of morals as consequent upon it. On this I have remarked 
at greater length in the Bampton Lectures, Lects. III. and VII. 

2 Compare Hume, Essay on the Academical Philosojihy , Fart ii. 



APPENDIX. 261 

edge in a sound philosophical spirit, alike removed from the idealism of 
Schclling and from the positivism of Comte, the writings of Dr. Whewell 
are especially valuable. To those who believe, with the present writer, 
that the future hopes of speculative philosophy rest on the possibility of 
a union of the critical principles of Kant with the sober practical spirit 
which is characteristic of English thinkers, the writings of the same 
author afford one of the most cheering assurances that the spirit of phi- 
losophy, under all its discouragements, is not yet extinct in this country. 
With this declaration, the spirit that has dictated the preceding criticism 
will not, I trust, be misunderstood. 1 



Note B, p. 128. 

That Berkeley was fully aware of the inconsequence of the conclusions 
which Hume afterwards attempted to draw from his principles, is manifest 
from the third Dialogue between Hylas and Philonous, in which he meets 
by anticipation the argument of the skeptic, 2 by maintaining that Ave are 
directly conscious of our own being. He is wrong, indeed, in calling this 
consciousness Reflection ; this term being properly applicable only to at- 
tention directed to our internal phenomena ; — an attention which does 
not make known, but presupposes, the attending self. But when he 
asserts, "I know or am conscious of my own being; and that I myself 
am not my ideas, but somewhat else, a thinking, active principle, that 
perceives, knows, wills, and operates about ideas," he states the true 
ground on which we may refute the skeptical conclusions of Hume. In- 
deed, this part of the Dialogue wants little more than a more complete 



1 The preceding note remains nearly as it appeared in the first edition of this 
work, published in 1851. Since that time, some additional remarks on the matter 
in question have appeared in Sir William Hamilton's Discussions, p. 323 (second 
edition, p. 335), in Dr. Whewell's Letter to the Author of Prolegomena Logica, 
and in the Author's pamphlet in reply, entitled, Tlie Limits of Demonstrative 
Science considered. Sir W. Hamilton's view is substantially the same as my 
own; and I cannot help regarding this independent coincidence as a confirma- 
tion of my original criticism. At the same time I feel bound to express my ac- 
knowledgments to Dr. Whewell for the instruction which his Letter has afforded 
me, and for the liberal and courteous tone in which his objections are urged. 

2 This part of Berkeley's Dialogue is meant as an answer to Locke, Essay, B. 
II. ch. 23, § 5, but the same reasoning is also valid against Hume. 



262 APPENDIX. 

exposition of the nature of the will to anticipate in principle the position 
afterwards taken against the great skeptic by Maine de Biran. 

The weak side of Berkeley's Idealism is not to he found in its relation 
to Hume, but in its relation to Fichte. The object proposed by Berkeley 
was to get rid of the contradictions and difficulties contained in the notion 
of matter as existing distinct from mind, and thus to leave the existence 
of minds, divine and human, beyond question. For this purpose he 
availed himself of two arguments, one of which was borrowed from the 
Cartesian philosophy, the other was added by himself. 

The Cartesians, denying the possibility of any direct influence of matter 
upon mind or of mind upon matter, explained the phenomena of percep- 
tion by the hypothesis of Divine Assistance and Occasional Causes. Ac- 
cording to this theory, the mental phenomena of sensation are not pro- 
duced by any direct action of body upon mind, but by the immediate 
agency of God, who produces certain sensations in the conscious mind, 
upon the occasion of certain corresponding movements in the bodily 
organism. 1 Berkeley, while denying the existence of matter, and there- 
fore rejecting the supposition of a bodily occasional cause, retained the 
Cartesian theory so far as to maintain that the presence of ideas in the 
mind is caused by the direct agency of the Deity. Thus he says, " When 
in broad daylight I open my eyes, it is not in niy power to choose whether 
I shall see or no, or to determine what particular objects shall present 
themselves to my view ; and so likewise as to the hearing and other senses ; 
the ideas imprinted on them are not creatures of my will. There is, there- 
fore, some other will or spirit that produces them." 2 

With this argument, which represents God as the efficient cause of our 
ideas, Berkeley combined another, in which the Deity is regarded as a 
constantly perceiving mind. Accepting, as allowed on all hands, the 
opinion that sensible qualities cannot subsist by themselves, and rejecting 
the ordinary hypothesis of their existence in an insensible substratum, he 
concluded that they must therefore exist in a mind which perceives them, 
and that they have no existence apart from being perceived. If, therefore, 



1 This theory is hinted at by Descartes, Principia, 1. ii. § 36, and more fully- 
elaborated by De la Forge, Traitc de Vesprit de I'homme, ch. xvi. ; Malebranche, 
Jiecherche de la Verite, 1. vi. p. ii. ch. 3; Entretiens sur la Metaphysique, Ent. 
a ii. Compare Laromiguiere, Legons de Philosophie, p. ii. 1. 9, and Hamilton, 
Lectures on Metajrtiysics, p. 208. 

2 Principles of Human Knowledge, § xxix. Compare §§ lvii. Ixii. In § liii. he 
expressly refers to some modern philosophers, i. e., the Cartesians, as agreeing 
with him in making God the immediate cause of all things. 






APPENDIX. 263 

they continue to exist when toe do not perceive them (and that they do so 
is the irresistible conviction of all men), they must he perceived by some 
other mind. Hence the continuous duration of things implies the exist- 
ence of a constantly percipient mind ; that is, of God. 1 

The relation between the divine and the human mind, as thus conceived, 
may be adapted cither to a presentative or to a representative theory of ideal- 
ism. We may hold that the ideas perceived at any particular time by a 
given man are numerically one with those constantly perceived by the 
Divine Mind; or we may regard them as having only a specific identity, 
the former being the copy, and the latter the archetype. Under the first 
hypothesis, the divine ideas are presented to us as the direct objects of our 
perception ; under the second, they are represented by similar ideas excited 
in ourselves. The former theory, though susceptible of various develop- 
ments in detail, is in principle that of Vision in God, and is accordingly 
distinctly maintained by Malebranche, who asserts that a thousand men 
can see the same individual object, namely, the intelligible extension which 
is perceived in God. 2 Berkeley, by rejecting the theory of Malebranche, 
was logically driven to the representative hypothesis, though his language 
occasionally wavers between the two. 3 

But to make this hypothesis the foundation of a theistic argument, it is 
necessary to retain, as Berkeley in fact did retain, the supposition of a real 
distinction between the idea or object perceived and the mind perceiving. 
The idea, though existing only as perceived and in the act of perception, 
must yet not be identified with that act, nor regarded as a mere modifica- 
tion or mode of being of the percipient mind. If this simpler form of 
representationism be once adopted, the legitimate inference is not Theism, 
but Pantheism. The ideas of which I am conscious being admitted to 
exist only as modes of my own being, it is concluded, by parity of reason- 
ing, that the archetypal world exists only in the form of various modes of 
the being of God. 

1 Principles of Human Knowledge, §§ xc. xci. ; Second Dialogue between Hylas 
and Philonous, sub init. 

2 See his Reponse au Livre des vraies et des fausses Idees, ch. xiii. 

3 I must acknowledge my obligations to Professor Webb, the author of " The 
Intellectualism of Locke," both for the instruction derived from his able and in- 
teresting work, and also for some unpublished communications on Berkeley's 
philosophy, of which I have availed myself in revising this note for the present 
edition. At the same time I am unable to agree with him in regarding Locke's 
and Berkeley's theory of ideas as identical with that of Arnauld, in which the 
representative idea is regarded as a modification of the mind. Indeed, in Berke- 
ley's system the relation of substance and mode has properly no place. 



264 APPENDIX. 

And such is in fact the form which Idealism assumes in the hands of 
Fichte and Schelling. The theory of perceptions essentially representative, 
which virtually regards the act and its immediate object as produced by 
the inherent power of the mind itself, was not, in Arnauld's hands, carried 
into any consequences beyond those required by his controversy with 
Malebranche. But a similar theory in the hands of the German philos- 
ophers became the basis, first, of an absolute Egoism, and filially, of an 
absolute Pantheism. Consciousness being only possible in the form of 
this or that special modification, it is but one step further to regard the 
true substance as an unmodified substratum existing out of consciousness, 
though manifested only in the consciousness of its several modes. We 
have thus the Absolute Ego of Fichte, and, by a still further generalization, 
the Absolute Being of Schelling, which, as the one substance from which 
personal and impersonal phenomena alike proceed, may indifferently be 
called Ego or God; the conscious self and the objects of its consciousness 
being but opposite modes of the Divine One and All. 

Nor will the Idealism of Berkeley, however opposed to these conclu- 
sions, offer any effectual barrier against them. The distinction between 
ideas existing as objects in the mind, and ideas existing as modes of the 
mind, is too slight to stand against that tendency to simplification which 
forms at once the chief virtue and the chief vice of philosophical specula- 
tion. The natural judgment of mankind, which affirms the knowledge 
of an external world existing independently of perception, being once 
abandoned, the only question which remains is, how to account for the 
phenomena on the simplest hypothesis. And the simplest hypothesis is 
that which postulates only one real existence underlying the multiplicity 
of phenomena, the hypothesis whose various subordinate theories all 
finally converge in Pantheism. 

These consequences can only be avoided by abandoning the Idealistic 
theory, and substituting a Natural Realism, Dualism though it be. Admit, 
with Berkeley, that the real things are those very things which I see and 
feel and perceive by my senses; but deny his other main position, that the 
mind perceives only its own ideas. We may thus open the way for the 
direct recognition in consciousness, first of our own organism as extended, 
and secondly of an external world in relation to that organism. 1 On this 
theory we may get rid of the metaphysical distinction between phenomena 
And noumena, or between representations and things in themselves. The im- 
mediate object of perception is the thing ; and the representation is not 
opposed to the unperceived thing in itself, but to the presentation, or thing 
as given in immediate relation to the conscious subject. 

1 See Sir "W. Hamilton's edition of Reid's Works, Notes D and D*. 



APPENDIX. 265 

' Another weak point of Berkeley's philosophy is his theory of the nature 
of Belief. He considers that real things differ from chimeras in being 
more vivid and clear, and not dependent on the will. This accords with 
Hume's definition of Belief, "A lively idea, related to or associated with 
a present impression." But the will is completely inactive in a dream; 
and phantasms may be as lively and vivid when excited by a fiction as by a 
true relation. The truth is that Belief cannot be denned, being presup- 
posed in all consciousness. Every act of consciousness is a judgment, 
and therefore a belief in the presence of its object: the question of reality 
or unreality depends upon where and how we judge it to be present. If an 
object present to the imagination is declared to be present to the sense, the 
judgment is false; but the object is unreal only if by real we mean sensible. 
All presentations, as such, may be called real relatively to their proper 
intuition, and unreal relatively to any other. The further question, which 
of our intuitions indicate the presence of external objects, and which are 
merely affections of the mind or the sensitive organism, is one which, 
hoAvever important on the realist hypothesis, is out of place in a system 
of idealism. 1 



Note C, p. 131. 

The following is Sir William Hamilton's analysis of the causal judg- 
ment, as the result of the mental law of the conditioned. " The phenom- 
enon is this : — When aware of a new appearance, we are unable to conceive 
that therein has originated any new existence, and are, therefore, constrained 
to think that what now appears to us under a new form had previously 
an existence under others, — others conceivable by us or not. These others 
(for they are always plural) are called its cause; and a cause (or, more 
properly, causes) we cannot but suppose; for a cause is simply eveiy thing 
without which the effect would not result; and all such concurring, the 
effect cannot but result. We are utterly unable to construe it in thought 
as possible that the complement of existence has been either increased or 
diminished. We cannot conceive, either, on the one hand, nothing be- 
coming something, or, on the other, something becoming nothing. When 
God is said to create the universe out of nothing, we think this by sup- 
posing that he evolves the universe out of nothing but himself; and, in 

1 For some remarks on this question, see the Author's article Metaphysics, in 
the eighth edition of the Encyclopedia Britannica, p. 613. 

23 



266 APPENDIX. 

like manner, we conceive annihilation only by conceiving the creator to 
withdraw his creation, by withdrawing his creative energy from actuality 
into power." 

" Our judgment of causality," he continues, "simply is: — We necessa- 
rily deny, or, rather, are unable to affirm in thought, that the object which 
we apprehend as beginning to be, really so begins; but, on the contrary, 
affirm, as we must, the identity of its present sum of being with the sum 
of its past existence. And here it is not requisite for us to know, or even 
to be able to conceive, under what form or under what combination this 
quantum previously existed; in other words, it is unnecessary for us to 
recognize the particular causes of this particular effect. A discovery of 
the determinate antecedents into which a determinate consequent may be 
refunded, is merely contingent, — merely the result of experience ; but the 
judgment that every event should have its causes, is necessary, and im- 
posed on us as a condition of our human intelligence itself. This necessity 
of so thinking is the only phenomenon to be explained. The question of phi- 
losophy is not concerning the cause, but concerning a cause." 1 

Such is Sir W. Hamilton's statement of the phenomenon. The follow- 
ing is his explanation of it. 

"The phenomenon of Causality seems nothing more than a corollary 
of the law of the Conditioned, in its application to a thing thought under 
the form or mental category of Existence Relative in Time. We cannot 
know, we cannot think a thing, except under the attribute of Existence ; 
we cannot know or think a fking to exist, except as in Time ; and we 
cannot know or think a thing to exist in Time, and think it absolutely to 
commence or terminate. Now this at once imposes on us the judgment of 
causality. Unable positively to think an absolute commencement, our 
impotence to this drives us backwards on the notion of Cause; unable 
positively to think an absolute termination, our impotence to this drives us 
forwards on the notion of Effect." " We are compelled," he continues, 
" to believe that the object (that is, the certain quale and quantum of being 
whose phenomenal rise into existence we have witnessed) did really exist, 
prior to this rise, under other forms (and by form, be it observed, I mean 
any mode of existence, conceivable by us or not). But to say that a thing 
previously existed under different forms, is only to say in other words 
that a thing had causes. (It would be here out of place to refute the error 
of philosophers in supposing that anything can have a single cause; — 
meaning always by a cause that without which the effect would not have 
been. I speak of course only of second causes, for of the Divine causa- 
tion we can pretend to no conception.") 2 

l Discussions, pp. 609, 610 (2d edition). 2 Discussions, pn. 618, 621. 



APPENDIX. 267 

To these extracts from Sir W. Hamilton's Discussions may be added a 
short passage from the Appendix to his Lectures on Metaphysics, containing 
his latest explanation of his theory. 1 " Causation is, therefore, necessarily 
within existence; for we cannot think of a change either from non-exist- 
ence to existence, or from existence to non-existence. The thought of 
power, therefore, always precedes that of creation, and follows that of 
annihilation; and as the thought of power always involves the thought 
of existence, therefore, in so far as the thoughts of creation and annihila- 
tion go, the necessity of thinking a cause for these changes exemplifies 
the facts, — that change is only from one form of existence to another, 
and that causation is simply our inability to think an absolute commence- 
ment or an absolute termination of being. The sum of being (actual and 
potential) now extant in the mental and material worlds, together with that 
in their Creator, and the sum of being (actual and potential) in the Creator 
alone, before and after those worlds existed, is necessarily thought as pre- 
cisely the same. Take the instance of a neutral salt. This is an effect, 
the product of various causes, — and all are necessarily powers. We have 
here, 1. an acid involving its power (active or passive) of combining with 
the alkali; 2. an alkali, involving its power (active or passive) of combin- 
ing with the acid; 3. (since, as the chemical brocard has it, ' Corpora non 
agunt nisi soluta') a fluid, say water, with its power of dissolving and 
holding in solution the acid and alkali; 4. a translative power, say the 
human hand, capable of bringing the acid, the alkali, and the water, into 
correlation, or within the sphere of mutual affinity. These (and they 
might be subdivided) are all causes of the effect; for, abstract anyone, 
and the salt is not produced. It wants a coefficient cause, and the con- 
currence of every cause is requisite for an effect/' 

In describing the above four conditions as all in different ways causes of 
the effect, Sir W. Hamilton will probably meet with the concurrence of 
most of his readers ; but the further statement, that these causes are all 
forms under which the effect previously existed, Avill probably strike them 
as being at least verbally different from the common view. Most men 
would readily admit that the acid, and the alkali, and the portion of water 
necessary for combining them, are but previous forms of the salt itself; 
but they would hesitate to admit the hand or its action into the same list. 
In other words, they would allow that the earlier and the later substances 
are identical in the material particles of which they are composed; but 
they would insist on distinguishing these particles from the efficient cause 
by which the composition is effected. But when the identity is stated in 
this way, the judgment assumes a totally new character. Whether it be 

, l Page 690. 



268 APPENDIX. 

true or not that we cannot conceive the quantity of existence to be increased 
or diminished, there is at any rate no such inability as regards the quantity 
of matter. It may be true as a fact that no material atom has been added 
to the world since the first creation; but the assertion, however true, is 
certainly not necessary. The power which created once must be conceived 
as able to create again, whether that ability is actually exercised or not. 

The same conclusion is still more evident when we proceed from the 
consideration of matter to that of mind. Of matter we maintain that the 
creation of new portions is perfectly conceivable, as a result at least, if 
not as a process ; of mind we believe that such creation actually takes 
place. Every man who comes into the world comes into it as a distinct 
individual, having a personality and consciousness of his own; and that 
personality is a distinct accession to the number of persons previously 
existing. Whatever may be thought concerning the material particles of 
which my body is composed, it cannot be maintained that I, as a person, 
had a previous existence in the personality of my parents, however I may 
regard them as the causes of my being. 

If, then, we are to identify the effect with the sum of its causes, we must 
rise above the conceptions of matter as matter and of mind as mind, and 
rise to the highest abstraction of existence in general, which is not any 
particular existence. "The sum of being (actual and potential) now ex- 
tant in the mental and material worlds, together with that in their Creator, 
and the sum of being (actual and potential) in the Creator alone, before 
and after those worlds existed, is necessarily thought as precisely the 
same." This assertion involves a previous question: Is Being in this 
abstract form necessarily thought as a sum at all, or indeed necessarily 
thought in any way ? 

It is admitted that Ave not only can conceive, but actually know by 
experience, the origination of new forms of existence : it is questioned 
whether these forms are regarded as new existences. But strip off the 
form", and what is left to constitute the existence ? The world, as a world, 
is not identical with its Creator; the Creator, as a Creator, is not identical 
with the world. The identity, if it is admitted at all, can only be admitted 
as regards an unmodified substratum of existence in general, which is no 
existence in particular. But existence, as an abstract substratum of this 
kind, is to human thought absolute zero : thus far the Hegelian paradox is 
true; pure being is pure nothing. When we have abstracted from the 
world all that distinguishes it as a world, and from the Creator all that 
distinguishes him as a Creator, we have nothing left to constitute the iden- 
tity of existence. From the mere general statement that cause and effect 
both exist, we have no more right to say that they are the same existence, 



APPENDIX. 269 

than, from the general statement that they Doth appear, we have a right 
to say that they arc the same phenomenon. 

Our conception of existence, as of appearance, is not singular, but 
plural. We are not conscious of existence in general, but of existing 
things ; as we are not conscious of appearance in general, but of apparent 
objects. The two may not indeed be always regarded as coextensive. 
Diversity of phenomena does not always imply diversity of existence ; but 
neither, on the other hand, does it always imply identity of existence. The 
primary fact of consciousness, the distinction between the ego and the non- 
ego, is a distinction, not of phenomena, but of realities. I know myself as 
a distinctly existing being ; — indeed, it is probably from that knowledge 
that my conception of being, as distinguished from appearance, is derived; 
— and I know the external world as something different from myself. 
Arguing by analogy from this primary conviction, I believe every man to 
be a distinct being from every other man and from all the other objects 
around him; and I believe that every new person that comes into the 
world is, as a person, a new existence. How far the same distinction may 
be extended to impersonal objects is another question; for in these we 
have no immediate knowledge of any principium individuationis, constitut- 
ing a single reality out of this or that aggregate of phenomena. But if 
we are unable to affirm the existence of such a principle, we are also 
unable to deny it; and hence we are not justified in asserting that all phe- 
nomena are but different modes of one and the same reality. 

From this point of view, the conception of potential existence, on which 
Sir W. Hamilton's theory mainly depends, vanishes altogether. If our 
conception of existence, like all other conceptions, is subject to the con- 
ditions of plurality and difference, — if we have no conception of being at 
all except in the form of this being as distinguished from that, — it fol- 
lows that, where the definite characteristics of this or that being are 
absent, the being itself has no existence in any form. The mere possi- 
bility of the existence of a man is not the existence of a man under an- 
other form; for the man, as such, has no existence except in the particular 
form by which he is actually constituted. To say that everything which 
begins had a previous existence in another form, is to say that the form is 
no part of the existence ; — a position which necessarily leads us back to 
the Eleatic theory of the unity of all things, and identifies Existence with 
Indifference. 

If these objections are tenable, the common statement of the causal 
judgment, in which the cause is regarded as something different from 
the effect, is more accurate, and more in accordance with the philosophy 
of the Conditioned, than that of Sir AY. Hamilton, in which the cause is 

23* 



270 APPENDIX. 

regarded as identical with the effect. Both statements equally repudiate 
the absurdity of supposing existence to have originated from absolute 
zero; for both alike suppose that nothing can begin to exist unless some- 
thing had previously existed. The question between them is merely this : 
Is this something a different existence, or only the same existence in another 
form ? 

Neither on the one supposition nor on the other do we obtain any pos- 
itive conception of the nature of Causation, beyond that which is furnished 
by, and limited to, our own volitions. Mere temporal antecedence of one 
thing to another is not the whole of causation, any more than the mere 
antecedence of the same thing under other forms. "We are compelled still 
to ask, what is that peculiar relation between antecedent and consequent, 
by which the one gives birth to the other, or is changed into the other ? 
The origination of the consequent by the antecedent, and the evolution of 
the actual from the potential, alike require a further cause to account for 
them; and this causative energy, call it by what name you will, — power, 
effort, tendency, — still remains absolutely unknown, but is still supposed as 
absolutely indispensable. 



Note D, p. 143. 

The following is Mr. Mill's argument for the subjection of the human 
will to the law of physical causation: "To the universality which man- 
kind are agreed in ascribing to the Law of Causation, there is one claim 
of exception, one disputed case, that of the Human Will; the determi- 
nations of Avhich a large class of metaphysicians are not willing to regard 
as following the causes called motives, according to as strict laws as those 
which they suppose to exist in the world of mere matter. This contro- 
verted point will undergo a special examination when we come to treat 
particularly of the Logic of the Moral Sciences. In the mean time I may 
remark, that those metaphysicians who, it must be observed, ground the 
main part of their objection upon the supposed repugnance of the doc- 
trine in question to our consciousness, seem to me to mistake the fact 
which consciousness testifies against. What is really in contradiction to 
consciousness, they would, I think, on strict self-examination, find to be 
the application to human actions and volitions of the ideas involved in 
the common use of the term Necessity; which I agree with them in think- 
ing highly objectionable. But if they would consider that by saying that 



APPENDIX. 271 

a man's actions necessarily follow from his character, all that is really 
meant (for no more is meant in any case whatever of causation) is that 
he invariably does act in conformity to his character, and that any one 
who thoroughly knew his character could certainly predict how he would 
act in any supposable case; they probably would not find this doctrine 
either contrary to their experience or revolting to their feelings. And no 
more than this is contended for by any one but an Asiatic fatalist." l 

And no more than this, we might add, is needed to construct a system 
of fatalism as rigid as any Asiatic can desire. But we must proceed to 
Mr. Mill's further remarks in the Logic of the Moral Sciences. In this 
latter portion of his work, the author has done little more than repeat his 
belief that the law of causality applies in the same strict sense to human 
actions as to other phenomena, involving in both cases, not constraint, but 
"invariable, certain, and unconditional sequence;" so that, "given the 
motives which are present to an individual's mind, and given likewise the 
character and disposition of the individual, the manner in which he will 
act may be unerringly inferred : that if we knew the person thoroughly, 
and knew all the inducements which are acting upon him, we could fore- 
tell his conduct with as much certainty as we can predict any physical 
event." He adds a distinction, intended to rescue his theory from the 
charge of fatalism, as usually implied in the term Necessity. " That 
Word, in its other acceptations, involves much more than mere uniformity 
of sequence; it implies irresistibleness. Applied to the will, it only means 
that the given cause will be followed by the effect, subject to all possibil- 
ities of counteraction by other causes ; but in common use it stands for 
the operation of those causes exclusively which are supposed too power- 
ful to be counteracted at all." "The causes, therefore," he continues, 
" on which action depends, are never uncontrollable; and any given effect 
is only necessary provided that the causes tending to produce it are not 
controlled. That whatever happens could not have happened otherwise, 
unless something had taken place which was capable of preventing it, no 
one surely needs hesitate to admit." 2 

That there is some fundamental weakness in the above theory, appears 
almost on the surface, from the fact that so acute a thinker as Mr. Mill can 
imagine that he has saved the principle of causality from the charge of 
fatalism by this concluding sentence. That whatever happens could not 
have happened otherwise, imless something had taken place capable of pre- 
venting it, is indeed in one sense a perfectly harmless position, but also a 
perfectly unproductive one. It is the mere truism of the Nursery Rhyme: 

l Mill's Logic, vol. i. p. 419. 2 Mill's Logic, book vi. chap. 2. 



272 APPENDIX. 

_ " There was an old woman lived under a hill, 

And if she 's not gone, she lives there still." 

Examine it closer, and the question at once arises, Whence is this counter- 
acting something to come? If from myself, from a self-determined act of 
free will, this concedes the whole question at issue. If from an act of will 
determined by preexisting causes, or altogether from without, I am still 
in the iron grasp of Necessity. If the preventing circumstance, come 
whence it may, comes as the certain sequence of antecedent phenomena, I 
am still the slave of circumstances ; if otherwise, the whole resemblance 
between moral and physical causation vanishes. 

But let us go up to the fundamental principle of the theory itself. The 
conduct of a man, we are told, is the invariable consequent of motives 
present to his mind ; so that, given the motives and the man's character, 
we could certainly predict the action. Character, it must be observed, is 
not here to be understood in Aristotle's sense, as a disposition caused by a 
series of voluntary acts; it must be something coeval with the first act of 
so-called volition. At the earliest period at which I am capable of acting, 
I possess a character of some sort; and that character, together with the 
motives presented, determines certainly how I shall act. 

The plausibility of the theory arises from an ambiguity in the term 
motive. In knowing the phenomena present to a man's mind at the mo- 
ment of any act of volition, is it included that we are to know their relation 
to his will? If so, the supposed prediction is a mere begging of the ques- 
tion. When I know how he will be inclined to act, I know how he will act. 
If not, the advocate of the doctrine must succumb to the sophism of the 
Assinus Buridani, and concede that the unfortunate animal, between two 
bundles of hay exactly alike, must starve. The solution of this sophism, 
supposing, of course, that the ass in that instance represents a voluntary, 
and not merely a spontaneous agent, is likewise the solution of Mr. Mill's 
argument. What is meant by two bundles of hay exactly alike? They 
must be indistinguishable by sight, smell, touch, and so forth. But are 
objects exactly similar as regards the senses, therefore exactly similar as 
regax-ds the will? A lump of salt and a lump of sugar may be similar to 
the eye: are they therefore similar to the palate? If taste is not dependent 
upon another sense, why may not will be independent of all the senses? 
If, on the other hand, the two bundles of hay are to be exactly similar, 
as motives in relation to the will, the argument amounts to the mere truism, 
that if the ass does not choose one he will choose neithei*. 

Exactly the same fallacy runs through Mr. Mill's theory of the causality 
of actions. The so-called motives are either a set of phenomena viewed 



APPENDIX. 273 

in their relation to the will, or viewed out of that relation. If the former, 
the argument has long ago been refuted by Reid. 1 The strongest motive 
prevails; but I only know the strength of motives in relation to the will 
by the test of ultimate prevalence; so that this means no more than that 
the prevailing motive prevails. I have no measure of strength but its 
effects. I only know certain things to be motives at all by the fact of 
their ultimate prevalence. If, on the other hand, the phenomena are con- 
sidered out of their relation to the will, my consciousness testifies at once 
that my actions are not subject to the same invariable sequence as physical 
changes. I know, that is, whenever I lift my arm to my head, that it is at 
that moment in my power not to lift it; and that, the antecedent circum- 
stances being precisely the same, I may decide not to do so at any future 
time. But, says Mr. Mill, this decision of the will is itself a new antece- 
dent. 2 Certainly, a new antecedent to the act ; but with what propriety can 
it be called a new antecedent to itself? The question is not whether the 
act of motion follows certainly upon that of volition, but whether the act 
of volition follows certainly upon antecedent circumstances. The former 
sequence depends on purely physical laws; and the preventing causes, 
such as a stroke of paralysis, are purely physical also. But if the latter 
sequence is invariable also, we admit, not one new phenomenon, but mil- 
lions; since an opposite determination of the will can only come in with 
its determinant, and the determinant of that determinant, and so on, ad 
infinitum. For to suppose that two opposite volitions can follow from the 
same determinant is incompatible with the whole hypothesis of causality. 
If, on the other hand, the sequence of volition from given antecedents is 
variable, what becomes of the power of predicting a man's actions? The 
contingency of a single link affects all the subsequent portion of the 
chain. 

In reply, then, to the question, Are our volitions, like other events, the 
result of causes? Certainly not, in the only intelligible senses of the 
term. I have only two positive notions of causation: one, the exertion 
of power by an intelligent being; the other, the uniform sequence of phe- 
nomenon B from A. (A may here stand for a single phenomenon, or a 
group ; for that antecedent or sum of antecedents which constitutes the 
Sufficient Reason.) The former hypothesis is Fatalism. If my will results 



1 Active Poivers, Essay iv. ch. 4, p. 610, ed. Hamilton. 

2 Mr. Mill says, " The wish is a new antecedent." If this term is meant to be 
synonymous with will, it would be an improvement in language to change it; if 
it is meant to be synonymous with desire, the confusion of desire with will viti- 
ates his whole argument. 



274 APPENDIX. 

from the coercion of some other intelligence, I am the slave of Destiny. 
The latter hypothesis is Determinism, a necessity no less rigid than fatal- 
ism, besides being at variance with the whole testimony of consciousness 
and with the experience of every clay. Besides these two, there is no 
alternative but to admit, in the fullest sense, the freedom of the will, by 
denying the applicability of the principle of causality to human actions. 

"This objection, if not removed," says Mr. Mill, "would be fatal to the 
attempt to treat human conduct as a subject of science." Be it so. It is 
better to accept the consequence than to admit the alternative. But it is 
fatal only according to Mr. Mill's view of science. Ethology, as he con- 
ceives it, in relation to individuals, as the science of characters as they must 
be according to laws of physical and mental causation, I do believe to be, 
in its idea and pretensions, chimerical; but Ethics, as the science of such 
characters as they ought to be according to the laws of moral obligation, 
remains undisturbed, or, rather, more securely established. It seems to be 
forgotten by writers of this school that these two systems are absolutely 
exclusive of each other; that physical causation and moral obligation 
cannot in perfection exist side by side; and that where they do coexist, 
each must be in the inverse ratio of the other. In proportion as we extend 
the domain of Necessity, we must diminish that of Duty; and Necessity, 
notwithstanding all that Mr. Mill has advanced, I still believe to be the 
inevitable result of subjecting moral acts to the laws of physical causa- 
tion. But Ethology, in relation to classes of men, as affected by national, 
professional, educational, physiological, or even moral circumstances, may, 
notwithstanding, attain to a vast amount of important practical principles 
and rules, though still subject to the influence of individual contingency. 
The actuary of an insurance company, if he were to predict the duration 
of life of any one individual on the books of his office, would in all proba- 
bility guess wrong; — as a matter of fact, it is true, mainly from his igno- 
rance of physical circumstances; but as a matter of theory also, if we 
allow that the individual in question may falsify the prediction by a volun- 
tary act of suicide. But if the same experiment is tried on a sufficiently 
large scale, opposite errors will counteract each other, and the general 
approximate result attains almost to a moral certainty. The general re- 
sults of Ethology, as applied to classes, are dependent in a great degree 
on similar circumstances, and may attain to the same or a higher amount 
of practical utility. 

In the course of the above remarks I have purposely avoided touching 
on a subject alluded to by Mr. Mill, the compatibility of man's free-will 
with God's foreknowledge. This question is insoluble, because we have 
nothing but negative notions to apply to it. To enable us to determine 



APPENDIX. 275 

the exact manner in which an Infinite Intelligence contemplates succession 
in time, it would be necessary that our intelligence should be infinite also. 
In this, as in all other revelations of God's relation to man, we must be 
content to believe, without aspiring to comprehend. The fact of God's 
foreknowledge is all that is i-evealed to us: the manner He has left in 
darkness, and we cannot enlighten it. But we are not justified in rejecting 
what we can comprehend because we do not understand its possible rela- 
tion to what we cannot. 1 That no conceivable amount of information 
could enable a being of human constitution to predict with certainty the 
acts of another, is established by the same evidence of consciousness by 
which Ave know that there is a human constitution at all. How far the 
same conclusion can be transferred to other orders of finite beings, still 
less to an Infinite Intelligence, we have no data for determining. 

The Necessitarian theory has recently been stated anew, in two works, 
both of high ability and reputation, but written in very different spirits 
and with very different purposes. The author of the first of these works, 
while professedly writing in the name and in support of the principles of 
Necessitarianism, strenuously asserts, at the same time, the apparently 
opposite doctrine of the freedom of the will and the responsibility of man, 
and writes with the avowed purpose of reconciling these seemingly con- 
flicting beliefs. The author of the second work pushes his principles to a 
conclusion which cannot be otherwise understood than as exonerating 
human actions from all voluntariness, and their agents from all responsi- 
bility. The former of these works, Dr. McCosh's " Method of the Divine 
Government," is one from which I cannot dissent without extreme reluc- 

l " Sed quia jam Deum agnoscentes, tam immensam in eo potestatem esse per- 
cipimus, ut nefas esse putemus existimare, aliquid unquam a nobis fieri posse, 
quod ante non ab ipso fuerit prasordinatum ; facile possumus nos ipsos magnis 
difficultatibus intricare, si hanc Dei preordinationem, cum arbitrii nostri liber- 
tate conciliare, atque utramque simul comprehendere conemur. 

" Illis vero nos expediemus, si recordemur mentem nostram esse finitam ; Dei 
autem potentiam, per quam non tantum omnia, qua? sunt aut esse possunt, ab 
aeterno praescivit, sed etiamvoluit ac praeordinavit, esse infinitam: ideoque hanc 
qidem a nobis satis attingi, ut clare et distincte percipiamus ipsam in Deo esse; 
non autem satis comprehendi, utvideamus quo pacto liberas hominum actiones 
indeterminatas relinquat; libertatis autem et indifferentiae quae in nobis est, nos 
ita conscios esse, ut nihil sit, quod evidentius et perfectius comprehendamus. Ab- 
surdum enim esset, propterea quod non comprehendimus unam rem, quam sci- 
mus ex natura sua nobis esse debere incomprehensibilem, de alia, dubitare, quam 
intime comprehendimus, atque apud nosmet ipsos experimur." — Descartes, 
Principia, P. i. 40, 41. 



276 APPENDIX. 

tance, regarding it, as I do, as one of the most valuable contributions to 
Christian philosophy which the present age has produced. With many of 
the author's remarks on the present question I fully concur, and in others 
I am inclined to hope that the difference between us is more verbal than 
real. But there are some of his statements which, even if not substan- 
tially erroneous in themselves, may lead to error from their language and 
its associations. 

Dr. McCosh takes his position, as a Necessitarian, on the ground "that 
the principle of cause and effect reigns in the domains of mind as in the 
territories of matter." 1 Thus he considers the doctrine of Necessity to 
be founded " on one of the very intellectual intuitions of man's mind, 
which leads us, in mental as in material phenomena, to anticipate the 
same effects to follow the same causes." Of this intellectual intuition he 
says, in another part of his work, " In regard to any one thought or feel- 
ing, we affirm that it must have had a cause in some property of the mind, 
or in some antecedent state of the mind, or in the two combined. It is by 
an intuition of our nature that we believe that this thought or feeling 
could not have been produced without a cause, and that this same cause 
will again and forever produce the same effects. And this intuitive princi- 
ple leads us to expect the reign of causation, not only among the thoughts 
and feelings generally, but among the wishes and volitions of the soul." 2 

I cannot help thinking that what Dr. McCosh here describes as an intu- 
itive principle of the mind, is in fact a combination of two principles, 
differing both in their nature and in their origin. That a given phenome- 
non, whether material or mental, " could not have been produced without 
a cause," is one assertion ; that " this same cause will again and forever 
produce the same effects," is another. Setting aside for the moment what 
we know empirically of the uniformity of nature, it is perfectly conceiv- 
able that the world might have been so constituted that there should be 
no regularity in the succession of events, but that the same cause which 
at one time is followed by a particular effect should at another have no 
such consequence. The latter portion, therefore, of Dr. McCosh's princi- 
ple is not entitled to rank among the original intuitions of the mind, 
because, even if experience assures us that, as a matter of fact, it never is 
violated, we have no difficulty in conceiving that it map be. 

But when the knowledge of the uniformity of nature is discarded, what 
remains to constitute the intuitive principle? How much or how little is 
implied in the mere conviction that every phenomenon must have a cause 
on the particular occasion of its occurrence, if we know nothing about 

l Appendix, p. 541. 2 p. 275. 



APPENDIX. 277 

similiarity of recurrence ? In the first place, with regard to voluntary and 
involuntary phenomena alike, it is implied that some other phenomenon 
has immediately preceded. This is a necessary consequence of the sub- 
jection of our consciousness to the law of time. In the next place, with 
regard to voluntary actions alone, of which I am the cause, it is implied 
that, at the moment of doing them, I am conscious of being able to abstain 
from them; and this is an immediate consciousness of power, in the proper 
sense of the term. In the third place, with regard to involuntary occur- 
rences, there is the assumption of an unknown something in the antecedent 
phenomenon analogous to the productive power in voluntary agents. 1 
This unknown something, however, is not power in the only form in which 
we are conscious of it; nay, it is the direct negation of it; for power is 
positively conceived only in the form of ability to choose between two 
alternatives .2 

It seems, then, that the apparent universality of the axiom, " Every event 
must have a cause," is partly due to the ambiguity of its terms. Define 
clearly what is meant by a cause, and the general axiom is at once divided 
into two special ones. I am the cause of my actions, inasmuch as I do 
them voluntarily, with a power at the same time to abstain from them. 
In this sense we cannot speak of a cause in relation to the phenomena of 
matter. It is not in this sense that the heat of the fire is the cause of the 
melting of the wax. On the other hand, in the sense in which Hume and 
Brown define a cause, it is applicable to material phenomena, but not to 
voluntary actions. A cause, in the sense of these philosophers, means 
some one invariable antecedent, or group of antecedents, the presence of 
which is always followed by the phenomenon in question. In this sense, 
it cannot be asserted that the determinations of the will have a cause, 
meaning that the will is always determined in a similar manner by the 
presence of similar antecedent circumstances. Or, thirdly, if we discard 

1 See above, p. 134. 

2 Dr. McCosh, p. 526, maintains that" power is implied in our very idea of sub- 
stance," and that "this power, these properties of substances, are permanently 
in them, and ready to be exercised at all times." But power, in this sense, is not 
an idea distinct from the actual sequence of the effect; it is merely that sequence 
viewed hypothetically. When I speak of the power of fire to melt wax, that 
power not being in actual exercise, I mean no more than that the melting would 
follow if the wax were exposed to it. In this sense we know nothing of power 
or property except as the manifestation of an effect, hypothetical or actual. 
Moreover, power in this sense, as a permanent property, involves the empirical 
idea of the uniformity of nature as well as the mere conception of a substance 
as existing. 

24 



278 APPENDIX. 

the conception of invariability, the axiom indeed becomes universal, but 
does not amount to an assertion of a cause. It then asserts positively no 
more than that every phenomenon has some other preceding it; i. e., that 
no given phenomenon can be conceived as standing at the beginning of 
all time. The unknown something, which we term power in the cause to 
produce its effect, can neither be included in this universal assertion nor 
referred to an original intuition of the mind; for there can be no intuition 
of that which is unknown, and no universality in that which is denied of 
one class of actions in the only sense in which it is affirmed of another. 

But it is urged on the other side that human actions can be calculated 
beforehand, and therefore are clearly subject to the operation* of law. 
" We anticipate," says Dr. McCosh, " the voluntary actions of mankind, 
as we anticipate their judgments. No doubt we are at times mistaken in 
the one case as in the other in our anticipations, but we do not in these 
cases conclude that the voluntary actions of mankind have had no cause, 
any more than we infer that their judgments have had no cause ; we con- 
clude merely that we did not know the cause, and that if we had known 
the full cause, we could have certainly anticipated the result. There are 
statistics of the voluntary actions of mankind — as of crimes, for in- 
stance — which are as accurate as the laws of mortality." 1 This state- 
ment would be a sufficient answer to a theory of complete indifference, 
which regards the will as entirely uninfluenced by motives up to the time 
when its choice is made; but it does not meet the objections of those who, 
while fully allowing the influence of motives, yet maintain that that in- 
fluence is different in its nature from any relation of material phenomena, 
and therefore should not be called by the same name. Doubtless there 
are general anticipations to be drawn from mental inclinations no less than 
from physical successions. If I throw a piece of wax into the fire, I ex- 
pect that it will melt. If I offer money to an avaricious man, I expect 
that he will take it. The question is : Is the expectation in both cases 
equally certain? or is the difference only such as can be accounted for by 
our greater or less knowledge of circumstances? To assume this is to 
beg the entire question; and, on the strength of this assumption, to call 
both relations by the common name of causation, is only to confound to- 
gether two different things under an ambiguity of language. 2 

i p. 276. 

2 " If in moral reasoning it be mere mockery to use the language of demon- 
stration, and to build up systems by trains of d priori reasoning upon a single 
principle; it is assuredly not less absurd to affect tbe forms of inductive proof 
in political speculation. Every political as well as every moral principle practi- 
cally involves the determination of the will, and thereby becomes at once sepa- 



APPENDIX. 279 

Dr. McCosh himself admits the existence of a self-activity of the will; 
which, if it means anything, means a power of resisting or yielding to 
the motives presented to it, and of resisting at one time and yielding at 
another, the concurrent circumstances being identical on both occasions. 
Is there anything similar to this in the relation of a physical cause to its 
effect? If not, why call two dissimilar things by the same name? 1 

In the other work to which I have above alluded, Mr. Buckle's " History 
of Civilization in England/' the "statistics of the voluntary actions of 
mankind " are adduced to prove a further conclusion, which not merely 
subjects every moral agent to the law of causation, but apparently exempts 
him from all personal responsibility. Rejecting " the metaphysical dogma 
of free-will," as resting on the fallible testimony of consciousness, Mr. 
Buckle maintains that the actions of men "vary in obedience to the 
changes in the surrounding society; " and "that such variations are the 
result of large and general causes, which, working upon the aggregate of 
society, must produce certain consequences, without regard to the volition 
of those particular men of whom the society is composed." 2 And in 
applying this doctrine to particular cases, he carries it out so consistently 
as to maintain, " that suicide is merely the product of the general condi- 



rated from that class of investigations in which we consider the immutable rela- 
tions of physical phenomena. That the will is influenced by motives, no one 
pretends to deny; but to compare that influence to a physical cause, followed 
by an unvaried physical effect, is only to confound things essentially different, 
and must ever end in metaphysical paradox or practical folly." — Sedgwick, 
Discourse on the Studies of the University of Cambridge, p. 81, fifth edition. 

1 The above remarks were written before the publication of Dr. McCosh's 
recent work on the " Intuitions of the Mind." I do not find any substantial dif- 
ference between the author's view, as stated in this later work, and that previ- 
ously given in the " Method ; " though there are some expressions which tend to 
confirm my suspicion that the difference between us is more verbal than real. 
Thus he asserts (p. 472) that " causation in the will is entirely different from 
causation in other action; " a statement in which I fully concur, only doubting 
the propriety of calling the former by this name of causation at all. If there is 
a causation, though of a different kind, in moral as well as in physical action, 
the generic notion of cause should be the same in both, the specific features alone 
being different, as distinguishing this kind of cause from that. But can any uni- 
vocal generic notion be pointed out, amounting to an adequate conception of 
causation as such? If not, the definition of causation, as a common genus, is 
not the same in both, and we have not the subdivisions of a generic notion, but 
only the different senses of an equivocal term. 

2 p. 21. 



280 APPENDIX. 

tion of society, and that the individual felon only carries into effect what 
is a necessary consequence of preceding circumstances." " In a given 
state of society/' he continues, " a certain number of persons must put 
an end to their own life. This is the general law; and the special question 
as to who shall commit the crime depends of course upon special laws, 
which, however, in their total action, must obey the large social law to 
which they are all subordinate. And the power of the larger law is so 
irresistible, that neither the love of life nor the fear of another world can 
avail anything towards even checking its operation." 1 This conclusion 
he endeavors to support by the evidence of statistics, " a branch of knowl- 
edge which, though still in its infancy, has already thrown more light on 
the study of human nature than all the sciences put together." 2 

It is surprising that this acute writer should not have seen that, in oppos- 
ing the evidence of statistics to that of consciousness, he is comparing 
together two witnesses who are not speaking of the same thing. The 
fact to which consciousness bears witness is the freedom of our own per- 
sonal actions. The fact which the statistical evidence is adduced to prove 
is the recurrence, within certain limits of greatest and least frequency, of 
actions distributed over an entire community. The former evidence tells 
us nothing directly concerning the actions of societies; the latter tells us 
nothing directly concerning the actions of individuals. 'Nay, it is precisely 
because the individual actions are not reducible to any fixed law, or capa- 
ble of representation by any numerical calculation-, that the statistical 
averages acquire their value as substitutes. No one dreams of applying 
statistical averages to calculate the period of the earth's rotation, by 
showing that four and twenty hours is the exact medium of time, com- 
paring one month's or one year's revolutions with another's. It is only 
where the individual movements are irregular that it is necessary to aim 
at a proximate regularity by calculating in masses. To what cause the 
individual irregularity is due, whether to the complexity and minuteness 
of the physical conditions of the problem, or to the presence of moral 
conditions and free agency, — whether it indicates contingency in the facts 
themselves, or only a defect in our means of calculating, — this is a 
question which can only be answered by an acquaintance with the indi- 
vidual objects under examination, and which gains no elucidation from 
the statistics of large classes. 3 

i pp. 25, 26. 2 p . 31. 

3 Some good remarks on the fallacy of this kind of reasoning will he found in 
the Rev. "W. B. Jones's Assize Sermon, The Responsibility of Man to the Law of 
God. Oxford, 1859, p. 15. 



APPENDIX. 281 



Note E, p. 145. 

Sir W. Hamilton, in connection with his theory of the nature of the 
causal judgment, maintains that the schemes of liberty and necessity are 
"both equally inconceivable; though for the fact of liberty we have, imme- 
diately or mediately, the testimony of consciousness. A free volition, ho 
tells us, is inconceivable, because we cannot conceive an absolute com- 
mencement ; a scheme of necessary determination is equally inconceivable, 
because we cannot conceive an infinite non-commencement. "As equally 
unthinkable," he says, " the two counter, the two one-sided, schemes are 
thus theoretically balanced. But, practically, our consciousness of the 
moral law, which, without a moral liberty in man would be a mendacious 
imperative, gives a decisive preponderance to the doctrine of freedom 
over the doctrine of fate. We are free in act, if we are accountable for 
our actions." 1 

This theory, though differing somewhat in the mode of reasoning, is in 
its conclusion similar to that previously arrived at by Kant. That philos- 
opher, in his third Contradiction of Transcendental Ideas, arranges in 
parallel columns the opposite arguments in behalf of Liberty and Neces- 
sity, with the view of showing that each is irresistible in its attack upon 
the other. Kant, too, like Sir W. Hamilton, maintains that the fact of 
liberty is guaranteed by the testimony of the moral law, whose Categor- 
ical Imperative thou shall necessarily implies a corresponding thou canst .2 
Kant, however, denies that the liberty as a fact can claim the direct testi- 
mony of consciousness; for consciousness in his philosophy is limited to 
the phenomena existing in space and time; whereas the freedom guar- 
anteed by the moral law is a purely transcendental idea, subject to no 
conditions of time, and incapable of being presented in experience. 3 
And this conclusion, so far as its negative result, the denial of a conscious- 
ness of freedom, is concerned, cannot be avoided, so long as we maintain, 
along with the universal authority of the principle of causality, the posi- 
tion that we are not directly conscious of self as a reality, but only of 
its several modes and affections. If my first consciousness relative to 
volition is not that of myself as willing, but only of will as a phenomenon, 
— if in the judgment " I will" there is no consciousness of I, but only of 

1 Discussions, pp. 624, 625. Compare Heid's Works, pp. 599, 602. 

2 See Kritik der reinen Vernunft, pp. 353, 429, 622; Metaph. der Sitten, p. 97; 
Xr. der pr. V. p. 139; Religion innerhalbu. s. w. p. 56, ed. Eosenkranz. 

3 Kritik der r. V. p. 414; Metaph der Sitten, p. 92; Kr. der pr. V. p. 224. 

24* 



282 APPENDIX. 

will, — to this phenomenon of volition I am compelled by the principle of 
causality to suppose an antecedent determining phenomenon; and to that 
again another, and so on ad infinitum. 

But this conclusion is no longer forced upon us, if we admit the exist- 
ence of an immediate consciousness, not merely of the phenomena of 
mind, but of the personal self as actively and passively related to them. 
We thus obtain for the fact of liberty not merely the indirect testimony 
of consciousness through the medium of the moral law, but the direct 
testimon} r by the presence of the fact itself. I am conscious not merely 
of the phenomenon of volition, but of myself as producing it, and as 
producing it by choice, with a power to choose the opposite alternative. 
In this case I am not compelled to go back to any prior cause whatever. 
I need not suppose a prior intelligent cause ; for my only positive notion 
of such a cause is myself determining, which does not imply myself deter- 
mined. I need not suppose a prior phenomenal cause ; for I am conscious 
of the influence of motives as inclining only, not as necessitating. The 
whole point at issue thus turns on the following question : Can the fact of 
consciousness expressed in the judgment I will, be analyzed into a relation 
of phenomena subject to the law of causality? Is the principle which we 
invariably apply to the sequence of one phenomenon on another also 
applicable to the relation of any phenomenon to the one given cause, 
myself? 

Sir William Hamilton lays much stress on the impossibility of conceiv- 
ing an absolute commencement. If by this is meant that I cannot con- 
ceive myself standing at the beginning of all time, out of all relation to 
any antecedent series of phenomena, it is undeniably true. But is such a 
conception needed to render the scheme of Liberty comprehensible? Is 
it not sufficient for me to know that none of the chronological antecedents 
stand to my volition in the particular relation of a determining cause? 
And this is the case if it is neither given as an active power coercing, nor 
as a passive phenomenon invariably preceding. To say that some antece- 
dent or other must go before my will, is only to say that I do not stand at 
the beginning of all time; but does this imply some one antecedent which 
is invariably followed by volition, or some active power, necessitating in 
each particular case ? If, on the presence of the antecedent, or group of 
antecedents, A, my volition sometimes takes place one way, and some- 
times another, it is not determined in the same manner as physical phenom- 
ena. If there is not always present some conscious being, exerting his 
power over my will, it is not determined in the same manner as it deter- 
mines its own volitions. But, excepting these two senses, what is meant 
by determining cause ? 



APPENDIX. 286 

Is there, then, extant any definition of will which does not imply another 
will preceding? Perhaps not; but the fault lies only in the authors of the 
definitions. To refute a given definition does not prove the non-existence 
of the thing denned. If liberty itself is a simple fact of consciousness, 
the error lies in the attempt to define it at all. The definition will neces- 
sarily involve a circle, and upon that circle, and not on the fact, the antag- 
onist reasons. But, then, if the definition and the fact of consciousness are 
at issue, the former must give way, not the latter. Now, consciousness tells 
me not that my will wills, but that I will. Is it necessary to the conceiv- 
ability of the fact that I should be able to analyze it into two constituent 
elements, — to place an abstract I on one side, and an abstract will on the 
other ; thus literally fulfilling the satirical direction for the turbulent 
Puritan's burial, by laying John apart from Lilburn and Lilburn from 
John ? Will any other state or act of mind bear a similar analysis ? Can 
I in any case separate the state from the mind and the mind from the 
state ; or give any definition which does not virtually repeat itself ? But 
is it correct, on that account, to call states which I experience every day 
in consciousness inconceivable ? 

If, indeed, the freedom of the will be supposed to mean an absolute indif- 
ference to and independence of motives, such a liberty would be not only 
inconceivable as a fact, but worthless as a principle of moral action. But 
such is not the liberty to which consciousness bears witness; nor is such a 
liberty required as the only alternative against fatalism. The influence of 
motives on the will is not denied ; only it is maintained that influence is 
not necessary determination; and that motives are not causes, in any 
proper sense of the latter term. Thus interpreted, I believe the scheme of 
liberty is inconceivable only if the determinist argument is unanswerable; 
and its answer is what I have attempted in this and the preceding note. 
If the attempt to establish a contradictory conclusion fails, liberty, though 
not definable, is surely as conceivable as any other simple datum of con- 
sciousness. 



Note F, p. 146. 

That our earliest notion of Causality arises from the fact given in the 
determination of our own volitions, is suggested by Locke, and established 
beyond all question by Maine de Biran. But then arises the question : By 
what process do we transcend our personal consciousness, and acknowl- 
edge, in relation to the changes of the sensible world, the operation of 



284 APPENDIX. 

causes other than ourselves? This process is called by De Biran and 
Royer-Collard a Natural Induction, a term severely criticized by M. Cousin. 
Were the process really inductive, he argues, we must believe every cause 
in nature to be, like ourselves, voluntary, conscious, and free; and even 
then the belief in question might perhaps be regarded as universally true 
within the limits of experience, but could never rise to the character of a 
necessary truth. For a more satisfactory explanation, M. Cousin has re- 
course to the principle of causality, which he regards as a necessary law 
of the reason, by virtue of which it disengages, in the fact of conscious- 
ness, the necessary element of causal relation from the contingent element 
of my personal production of this or that particular movement. This 
necessity, which compels the reason to suppose a cause whenever the 
senses or the consciousness present a phenomenon, is the Principle of 
Causality. 1 

It is obvious to ask, What do we gain by the principle of causality thus 
supposed ? Does it explain in any degree the nature of that power which 
we are supposed to attribute to inanimate objects ? Does it explain how 
we divest our original notion of the attribute of personality, and what is 
left when we have done so? Does it furnish the slightest hint or help for 
investigating the true character of efficient causes? By no means. The 
principle itself is a mere statement of the fact, that we do invariably sup- 
pose a cause of physical changes, and that we cannot but do so. It offers 
no psychological explanation of the fact; it merely gives it the name of a 
principle of reason. It does not give us any positive notion of the cause 
in question; this remains, we know not what, — a something different 
from our own causality, and, as such, supposable perhaps, but inconceiv- 
able. It does not tell us how we can attain to a more positive knowledge. 
Not by the senses; for these present to us only successive phenomena. 
Not by the internal consciousness ; for this informs us only of personal 
causation. Not by the reason; for this only tells us in general terms that 
there is a cause, but furnishes no means of observing and distinguishing 
its character and varieties. The cause of physical changes still remains, 
like the subject of physical attributes, a negative idea, aje ne sais quoi. 

Nor does M. Cousin's theory, any more than that of De Biran, explain 
how we get rid of the personal element with which all intuitive causality 
is involved. It only says that we do so, and that we must do so. The 
term Induction, employed by De Biran and Royer-Collard, is indeed objec- 
tionable, whether it be taken in the Aristotelian or in the Baconian sense. 
The former is objectionable, inasmuch as our personal acts are not sup- 

1 Cours de Philosophie, Le^on 19. 



APPENDIX. 285 

posed to constitute, or even adequately to represent, the whole body of 
causal relations. The latter is objectionable; for the same acts cannot be 
selected instances showing diverse operations of a law, but must, from the 
nature of the case, be all of one kind. But this objection aifects only the 
language, and not the basis of the theory; indeed, the two philosophers 
in question have expressly stated that their natural induction must be 
carefully distinguished from that of physics. 1 But in point of language, 
the phrase principle of reason is equally objectionable; partly as tending to 
check all further psychological investigation into a point by no means as 
yet satisfactorily explained, and partly as opening the way to the thousand 
extravagances of ontological speculation, by concealing the purely neg- 
ative character of the notion of physical power. On M. de Biran's theory, 
says M. Cousin, anthropomorphism becomes the universal and necessary 
law of thought. 2 It might be replied, that in all cases where the presenta- 
tion is given by internal consciousness only, anthropomorphism is in fact 
the condition and the limit of all positive thinking. 

I conceive, therefore, that there is nothing in M. Cousin's theory which 
dispenses with the obligation of a further psychological examination of 
the origin and character of the supposed principle of causality, such as I 
have attempted in the text of the present work. Whether that explana- 
tion itself be right or wrong, must be judged by others; but, whatever 
may be its fate in this respect, I shall deem its purpose sufficiently an- 
swered if it serves to call the attention of philosophers to a point hitherto 
too much neglected in speculation — the important distinction between 
positive and negative intuitions and thoughts. 



Note G, p. 148. 

In the controversy concerning the existence of a Moral Sense, the ques- 
tion at issue has suffered considerable misrepresentation from the want of 
au accurate distinction between intuitive or presentative consciousness, 
whose object is an individual thing, act, or state of mind, and reflective or 
representative consciousness, whose immediate object is a general notion 
or principle. Stewart, for example, in his Life of Adam Smith, observes : 

1 (Euvres de Maine de Biran, vol. iv. p. 393; Jouffroy's Reid, vol. iv. pp. 383, 
439. 

2 (Euvres de Maine de Biran, .vol. iv. Preface de l'Editeur, p. xxxvi. 



286 APPENDIX. 

"It was the opinion of Dr. Cudworth, and also of Dr. Clarke, that moral 
distinctions are perceived by that power of the mind which distinguishes 
truth from falsehood. This system it was one great object of Dr. Hutch- 
eson's philosophy to refute, and in opposition to it, to show that the words 
right and wrong express certain agreeable and disagreeable qualities in 
actions, which it is not the province of reason, but of feeling, to perceive; 
and to that power of perception which renders us susceptible of pleasure 
or of pain from the view of virtue or of vice, he gave the name of the 
Moral Sense." The same philosopher, in his Philosophical Essays, en- 
deavors to obviate Hume's deductions from Hutcheson's theory, by falling 
back, in some degree, upon the views of Cudworth and Clarke, and refer- 
ring the origin of our notions of right and wrong to reason instead of sense, 
" Tastes and colors," said Hume, " and all other sensible qualities, lie not 
in the bodies, but merely in the senses. The case is the same with beauty 
and deformity, virtue and vice." To this Stewart replies: "The decisions 
of the understanding, it must be owned, with respect to moral truth, 
differ from those which relate to a mathematical theorem, or to the result 
of a chemical experiment, inasmuch as they are always accompanied 
with some feeling or emotion of the heart; but on an accurate analysis of 
this compounded sentiment it will be found that it is the intellectual judg- 
ment which is the groundwork of the feeling, and not the feeling of the 
judgment." 

In a Lecture on Moral Relations, by the late Professor Mills, the differ- 
ent opinions concerning our perception of Morality are summed up as 
follows : 

" 1. Some ascribe our apprehension of it, with Hutcheson, to a peculiar 
internal sense, similar in its operations to the external senses, and con- 
found moral perception with taste; this is, strictly speaking, the theory 
of a moral sense. 

"2. Others attribute moral perception, not to any peculiar sense, but 
yet to a peculiar faculty of the understanding distinct from its general 
powers, and they appear to identify conscience with the moral faculty. 

" 3. Many deny the existence of a peculiar moral faculty, and maintain 
that moral principles are apprehended by the same powers of the intellect 
which perceive other kinds of truth. 

" 4. The Utilitarian theoiy implies that moral relations are ascertained 
and embraced by the operations of the discursive faculty only." 1 

The whole controversy may be considerably cleared by distinguishing 
Moral Facts from Moral Principles. Facts of all kinds are presented to, and 

1 Essays and Lectures by the late Rev. W. Mills, p. 204. 



APPENDIX. 287 

perceived by, different faculties of intuition, similar in the manner of 
their operation to the perceptions of sense; and hence, with some allow- 
ance for metaphor, we may speak of internal or external senses. 1 Is it 
then asked whether we discern morality in individual acts by the same 
faculties by which we discern other qualities of individual objects pre- 
sented to us ? But, of these qualities, some are visible, some audible, and 
so on. Is it meant that an act can literally be seen, heard, smelt, felt, or 
tasted, to be virtuous or vicious? If not, the perception of the moral char- 
acter of acts is a distinct presentation, and, as such, to be referred to a 
distinct faculty; though, being, as will appear, an object of internal, not 
of external perception, it is not, like the external senses, connected with a 
distinct bodily organ. 

The question, whether right and wrong are apprehended by the same 
powers of the intellect which perceive other kinds of truth, is only appli- 
cable to the general concepts or principles through which morality is repre- 
sented as an object of thought. Truth and Falsehood can be distinguished 
in representative knowledge only; and all such knowledge is most con- 
veniently classified by reference to the single faculty of the Understanding. 
The same power of thought may inquire into the ground of various pre- 
sentations; it may investigate, for example, why one object is white, why 
another is harmonious, why a third is sweet, why a fourth is beautiful, 
why a fifth is virtuous; but in all such investigations, the fact of a given 
object possessing a given quality must be presupposed as the groundwork 
of the investigation. The distinction between a true and a false theory of 
morals will be determined by the same test as that between truth and 
falsehood in any other inquiry — its agreement or not, with the facts as 
given in intuition. 

It thus appears that a power of discerning right and wrong in individ- 
ual acts must be allowed as the presentative basis, without which no 
system of Moral Philosophy is possible. Such a power, thus limited, it is 



l This has been observed by Aristotle, whose account of the Practical Sense, or 
Intelligence, is in this respect more accurate than that of modern philosophers. 
Kal yap rwv npooruv opoou Kal twv iaxaruiv uoiis icrrl Kal ov \6yos, Kal 6 /.df 
Kara ras a7ro8ei£eis rwv clkivt)tu)V opcav /cat irpcajcav, 6 8' iv rats rrpaKriKals 
rod 4o~x<* T ov Kal 4 u S e x o fM 4 v o v Kal rrjs er 4 pas ir p or d~ 
a 4 as ' apxal -yap rov ov eveKa avrar 4k rwu /ia^' eKacrra yap rb ko&6\ov. 
Tovrccu ohv eX 6tz/ ^ € * a? a &r] o~ iv, avrt] 8' eVrl vovs. — Eth. Nic. vi. 11. 
Compare Pol. i. 2: Tovro yap rrpbs raX\a £a>a ro7s avSpcaTrois tSiou, rb fiovov 
aya&ov Kal KaKOv Kal diKaiov Kal aS'iKOV Kal ra>v aXXoov a?o-&7)(r iv exeir. 
These passages may serve as a qualification of Smith's assertion, that the word 
moral sense is of very late formation. 



288 APPENDIX. 

impossible for the Utilitarian to explain away by any theory of association 
or education. Education may corrupt and pervert our presented ideas, 
but it cannot originate them : it may teach me to regard an act as right 
which is really wrong, or vice versa, but it cannot create the original im- 
pression of either. To deny, with Locke and Paley, the existence of a 
moral sense, because one man holds to be wrong what another holds to be 
right, is like denying the existence of a faculty of sight, because a man 
with the jaundice sees all objects yellow. The existence of the faculty is 
shown by our approving or disapproving at all ; it cannot therefore be 
disproved by the fact of our sometimes approving or disapproving wrongly. 
The opposite error of Hume, in holding that virtue and vice exist in the 
sense only, lies in a confusion of the subjective feeling of approbation 
with the objective quality which gives rise to it. The same confusion 
has taken place Avith regard to the secondary qualities of body. Heat and 
color, as sensations, exist only in a sentient being; but that such sensations 
originate from nothing at all in the bodies themselves, is an absurdity long 
ago exploded, if indeed ever seriously maintained. 

This presentation of right and wrong, however, is by no means accurately 
exhibited in the account commonly given of moral sense. It is not correct 
to describe our perception of the moral character of actions in general as 
coordinate with or including the judgment of our own conduct in particu- 
lar. 1 Right and wrong are not directly presented to me in any other actions 
than my own. If I see a murder committed in a puppet-show, I have all 
the same presented phenomena as if I see a murder committed by a man. 
I do not feel the same moral disapprobation, because I do not attribute to 
the puppet the same internal consciousness of obligation as to the man. But 
this consciousness is not presented except in the case of my own acts, and, 
from these, is transferred representatively to other men, whose mental consti- 
ttition I believe to be in this respect similar to my own. The intuitive faculty 
is properly limited to the approbation or disapprobation of my personal acts ; 
and to this personal consciousness must thus be traced the original notions 
of Eight and Wrong, as of Cause, and of Substance, and of all internal 
phenomena. Hence, if the terms Moral Sense and Conscience be used ac- 
cording to the ordinary philosophical distinction, it will be more correct to 
describe Moral Sense as an extension of Conscience, than Conscience as a 
limitation of Moral Sense. 2 

1 As is done by Bishop Sanderson, in his Prcelectiones de Obligatione Conscien- 
tice, as well as by Sbaftesbury, Hutcheson, and most of tbe advocates of a moral 
sense, and still more by Smitb, in his theory of Sympathy. 

2 This is exactly the reverse of the theory of Adam Smith, who maintains that 
our judgments concerning the morality of our own acts is entirely derived from 



APPENDIX. 289 



Note H, p. 212. 

The difference between the relations of the several Forms of Thought to 
Psychology and to Logic has not hitherto been accurately marked. Psy- 
chologically, all that is communicated by, not given to, the act of thinking, 
belongs to the form, not to the matter, of the product. But these psycho- 
logical forms do not come within the province of Logic, unless some 
further process of pure or formal thinking is affected by them. In its 
psychological relation, modality is clearly one of the forms of judgment. 
The necessary judgment, "A must be B," expresses the existence of a law, 
of some kind or other, by which the attributes are inseparably connected; 
the contingent judgment, whose full expression is, "A may or may not be 
B," denies the existence of any law of the kind; while the pure judgment, 
H A is B," states the fact of an existing connection, without taking into 
account the question of law at all. The psychological question is this: 
"Is the presence or absence of a law connecting the terms of a judgment 
given to or by the act of judging? Is it part of the given phenomena, or a 
manner in which the mind regards them ? In other words, Is modality an 
affection of the predicate, or of the copula? Do I in thought decide on 
the actual connection of A with a given necessary-B, or on the necessary 
connection of A with a given B ? In the former case, the modality belongs 
to the matter of the judgment; in the latter, to the form. 

The true answer to this question is sufficiently plain. If sensible experi- 
ence is incompetent to furnish the notion of identity between two phenom- 
ena, it is equally incompetent to furnish that of necessary or contingent 
identity. These are additional products of the act of thought ; experience 
having only presented the phenomena in a constant or variable juxtaposi- 
tion. Naj r , further, the hypothesis that modality is given in the predicate 
of a judgment, not thought in the copula, becomes, in ultimate analysis, 
destruetive of itself. For, if in thought we connect A with what is given 
as necessarily B, this implies that B has previously been thought as neces- 
sarily connected with some subject or other. A necessary-B has no intelli- 
gible sense, except in relation to some previous judgment, " C must be B." 
The identification of A with B, then, takes place through the medium of C ; 

that which we pass on others. This theory he carries so far as to assert, " Were 
it possible that a human creature could grow up to manhood in some solitary 
place, without any communication with his own species, he could no more think 
of his own character, of the propriety or demerit of his own sentiments and con- 
duct, of the beauty or deformity of his own mind, than of the beauty or deform- 
ity of his own face." 

25 



290 APPENDIX. 

and the supposition that modality can be given as an affection of the 
predicate, implies that it has been previously thought as an affection of the 
copula. This is sufficient to establish the psychological position of mo- 
dality as a form of the judgment. But, thus admitted, it is indispensable 
that it should be expressed in the copula, and not, as is frequently done, 
left to be gathered from our knowledge of the matter. A judgment of 
the form "A is B," whatever notions may be expressed by the terms, 
can never be thought as other than a pure or assertorial judgment. An 
apodeictical or problematical judgment requires a different statement of 
the copula relation, "A must be B," or "A may be B." 

On the other hand, the criticism of Sir W. Hamilton, though accurately 
expressed in relation to one process of thought only, may be so extended 
as to be decisive as regards the exclusion of modality from Logic. 
" Necessity, Contingency, etc.," he says, " are circumstances which do not 
affect the logical copula or the logical inference. They do not relate to the 
connection of the subject and predicate, of the antecedent and conse- 
quent, as terms in thought, but as realities in existence; they are met- 
aphysical, not logical conditions. The syllogistic inference is always 
necessary ; is modified by no extraformal condition ; is equally apodictic 
in contingent as in necessary matter." 1 

As regards the syllogistic inference, these remarks are strictly accurate, 
and would be conclusive against any modality proposed as a form of 
reasoning. Were a distinction, for example, set up between syllogisms in 
which the conclusion necessarily follows from the premises, and syllogisms 
in which it may be inferred with more or less probability, the latter would 
rightly be condemned as extralogical — the true syllogistic inference being 
always necessary. As regards the copula in judgments, the criticism 
cannot be accepted as verbally accurate unless we distinguish the logical 
copula from the psychological. That modality relates to realities in 
existence, is not conclusive; for quantity and quality, in all synthetical 
judgments, do the same in the same degree, and yet are rightly classed as 
forms of thought. But if we extend the distinction between formal and 
material thinking, so as to embrace judgment and conception, as well as 
reasoning, it is clear that the copula is always necessary in analytical or 
formal judging, as the inference is always necessary in formal reasoning. 
Material judgments, however, cannot be entirely excluded from Logic, in 
so far as they furnish data for formal reasoning. They are admissible, 
however, only in relation to this latter process ; and hence those forms of 
judgment only are rightly to be regarded as logical which affect the formal 
inference derivable from them. This is the case with quantity and quality, 

1 Discussions., p. 146. 



APPENDIX. 291 

but not with modality : the latter affects the conclusion of a syllogism not 
as a conclusion, in its relation to the premises, but only in itself, as a prop- 
osition. For this reason, it is logically preferable to exclude modality as 
a form, and to treat it as if it affected the predicate only of the judgment. 
The logical copula thus becomes in every instance assertorial only ; and if 
this be carefully distinguished from the psychological copula, the remarks 
of Sir W. Hamilton may be regarded as applicable to the whole of Logic, 
and to every process of thought. 



THE END 



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